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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>Parser Template</title>
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<meta name="viewport" content="width=device-width initial-scale=1">
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<script>
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<h1><a href="../index.html">
<img src="../docs-assets/Inform.png" height=72">
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<ul><li><a href="../index.html">home</a></li>
</ul><h2>Compiler</h2><ul>
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<main role="main">
<!--Weave of 'Parser Template' generated by Inweb-->
<div class="breadcrumbs">
<ul class="crumbs"><li><a href="../index.html">Home</a></li><li><a href="../extensions.html">Kits</a></li><li><a href="index.html">CommandParserKit</a></li><li><b>Parser Template</b></li></ul></div>
<p class="purpose">The parser for turning the text of the typed command into a proposed action by the player.</p>
<ul class="toc"><li><a href="S-prs.html#SP1">§1. Identification</a></li><li><a href="S-prs.html#SP2">§2. Parser Error Numbers</a></li><li><a href="S-prs.html#SP3">§3. Grammar Line Variables</a></li><li><a href="S-prs.html#SP4">§4. Grammar Token Variables</a></li><li><a href="S-prs.html#SP5">§5. Match List Variables</a></li><li><a href="S-prs.html#SP6">§6. Words</a></li><li><a href="S-prs.html#SP7">§7. Snippets</a></li><li><a href="S-prs.html#SP8">§8. Unpacking Grammar Lines</a></li><li><a href="S-prs.html#SP9">§9. Keyboard Primitive</a></li><li><a href="S-prs.html#SP10">§10. Reading the Command</a></li><li><a href="S-prs.html#SP11">§11. Parser Proper</a></li><li><a href="S-prs.html#SP12">§12. Parser Letter A</a></li><li><a href="S-prs.html#SP13">§13. Parser Letter B</a></li><li><a href="S-prs.html#SP14">§14. Parser Letter C</a></li><li><a href="S-prs.html#SP15">§15. Parser Letter D</a></li><li><a href="S-prs.html#SP16">§16. Parser Letter E</a></li><li><a href="S-prs.html#SP17">§17. Parser Letter F</a></li><li><a href="S-prs.html#SP18">§18. Parser Letter G</a></li><li><a href="S-prs.html#SP19">§19. Parser Letter H</a></li><li><a href="S-prs.html#SP20">§20. Parser Letter I</a></li><li><a href="S-prs.html#SP21">§21. Parser Letter J</a></li><li><a href="S-prs.html#SP22">§22. Parser Letter K</a></li><li><a href="S-prs.html#SP23">§23. End of Parser Proper</a></li><li><a href="S-prs.html#SP24">§24. Internal Rule</a></li><li><a href="S-prs.html#SP25">§25. Parse Token</a></li><li><a href="S-prs.html#SP26">§26. Parse Token Letter A</a></li><li><a href="S-prs.html#SP27">§27. Parse Token Letter B</a></li><li><a href="S-prs.html#SP28">§28. Parse Token Letter C</a></li><li><a href="S-prs.html#SP29">§29. Parse Token Letter D</a></li><li><a href="S-prs.html#SP30">§30. Parse Token Letter E</a></li><li><a href="S-prs.html#SP31">§31. Parse Token Letter F</a></li><li><a href="S-prs.html#SP32">§32. Descriptors</a></li><li><a href="S-prs.html#SP33">§33. Parsing Descriptors</a></li><li><a href="S-prs.html#SP34">§34. Preposition Chain</a></li><li><a href="S-prs.html#SP35">§35. Creature</a></li><li><a href="S-prs.html#SP36">§36. Noun Domain</a></li><li><a href="S-prs.html#SP37">§37. Adjudicate</a></li><li><a href="S-prs.html#SP38">§38. ReviseMulti</a></li><li><a href="S-prs.html#SP39">§39. Match List</a></li><li><a href="S-prs.html#SP40">§40. ScoreMatchL</a></li><li><a href="S-prs.html#SP41">§41. BestGuess</a></li><li><a href="S-prs.html#SP42">§42. SingleBestGuess</a></li><li><a href="S-prs.html#SP43">§43. Identical</a></li><li><a href="S-prs.html#SP44">§44. Print Command</a></li><li><a href="S-prs.html#SP45">§45. CantSee</a></li><li><a href="S-prs.html#SP46">§46. Multiple Object List</a></li><li><a href="S-prs.html#SP47">§47. Scope</a></li><li><a href="S-prs.html#SP48">§48. Scope Level 0</a></li><li><a href="S-prs.html#SP49">§49. SearchScope</a></li><li><a href="S-prs.html#SP50">§50. ScopeWithin</a></li><li><a href="S-prs.html#SP51">§51. DoScopeActionAndRecurse</a></li><li><a href="S-prs.html#SP52">§52. DoScopeAction</a></li><li><a href="S-prs.html#SP53">§53. Parsing Object Names</a></li><li><a href="S-prs.html#SP54">§54. TryGivenObject</a></li><li><a href="S-prs.html#SP55">§55. Refers</a></li><li><a href="S-prs.html#SP56">§56. NounWord</a></li><li><a href="S-prs.html#SP57">§57. TryNumber</a></li><li><a href="S-prs.html#SP58">§58. Gender</a></li><li><a href="S-prs.html#SP59">§59. Noticing Plurals</a></li><li><a href="S-prs.html#SP60">§60. Pronoun Handling</a></li><li><a href="S-prs.html#SP61">§61. Yes/No Questions</a></li><li><a href="S-prs.html#SP62">§62. Number Words</a></li><li><a href="S-prs.html#SP63">§63. Choose Objects</a></li><li><a href="S-prs.html#SP64">§64. Default Topic</a></li><li><a href="S-prs.html#SP65">§65. Recognition-only-GPR</a></li><li><a href="S-prs.html#SP66">§66. RunRoutines</a></li><li><a href="S-prs.html#SP67">§67. Setting the Player's Command</a></li><li><a href="S-prs.html#SP68">§68. Multiple Object List</a></li></ul><hr class="tocbar">
<p class="commentary firstcommentary"><a id="SP1" class="paragraph-anchor"></a><b>§1. Identification. </b></p>
<pre class="displayed-code all-displayed-code code-font">
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">COMMANDPARSERKIT</span><span class="plain-syntax"> = </span><span class="constant-syntax">1</span><span class="plain-syntax">;</span>
</pre>
<p class="commentary firstcommentary"><a id="SP2" class="paragraph-anchor"></a><b>§2. Parser Error Numbers. </b>The traditional ways in which the I6 library's parser, which we adopt here
more or less intact, can give up on a player's command.
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">STUCK_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">1</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">UPTO_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">2</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">NUMBER_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">3</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">ANIMA_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">4</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">CANTSEE_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">5</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">TOOLIT_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">6</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">NOTHELD_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">7</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">MULTI_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">8</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">MMULTI_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">9</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">VAGUE_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">10</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">EXCEPT_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">11</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">VERB_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">12</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">SCENERY_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">13</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">ITGONE_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">14</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">JUNKAFTER_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">15</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">TOOFEW_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">16</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">NOTHING_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">17</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">ASKSCOPE_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">18</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">NOTINCONTEXT_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">19</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">BLANKLINE_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">20</span><span class="plain-syntax">; </span><span class="comment-syntax">Not formally a parser error, but used by I7 as if</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">ANIMAAGAIN_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">21</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">COMMABEGIN_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">22</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">MISSINGPERSON_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">23</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">ANIMALISTEN_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">24</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">TOTALK_PE</span><span class="plain-syntax"> = </span><span class="constant-syntax">25</span><span class="plain-syntax">;</span>
</pre>
<p class="commentary firstcommentary"><a id="SP3" class="paragraph-anchor"></a><b>§3. Grammar Line Variables. </b>This is the I6 library parser in mostly untouched form: reformatted for template
file use, and with paragraph divisions, but otherwise hardly changed at all.
It is a complex algorithm but one which is known to produce good results for
the most part, and it is well understood from (at time of writing) fifteen
years of use. A few I7 additions have been made, but none disrupting the
basic method. For instance, I7's system for resolving ambiguities is
implemented by providing a <span class="extract"><span class="extract-syntax">ChooseObjects</span></span> routine, just as a user of the
I6 library would do.
</p>
<p class="commentary">The I6 parser uses a huge number of global variables, which is not to modern
programming tastes: in the early days of Inform, the parser was essentially
written in assembly-language only lightly structured by C-like syntaxes,
and the Z-machine's 240 globals were more or less registers. The I6 library
made no distinction between which were "private" to the parser and which
allowed to be accessed by the user's code at large. The I7 template does
impose that boundary, though not very strongly: the variables defined
in "Output.i6t" are for general access, while the ones below should only
be read or written by the parser.
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">etype</span><span class="plain-syntax">; </span><span class="comment-syntax">parser error number if command not recognised</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">best_etype</span><span class="plain-syntax">; </span><span class="comment-syntax">Preferred error number so far</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">nextbest_etype</span><span class="plain-syntax">; </span><span class="comment-syntax">Preferred one, if ASKSCOPE_PE disallowed</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">parser_inflection</span><span class="plain-syntax">; </span><span class="comment-syntax">A property (usually "name") to find object names in</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">indirect_parser_inflection</span><span class="plain-syntax">; </span><span class="comment-syntax">Set this to have parser_inflection called</span>
<span class="reserved-syntax">Array</span><span class="plain-syntax"> </span><span class="identifier-syntax">pattern</span><span class="plain-syntax"> --> </span><span class="constant-syntax">32</span><span class="plain-syntax">; </span><span class="comment-syntax">For the current pattern match</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">pcount</span><span class="plain-syntax">; </span><span class="comment-syntax">and a marker within it</span>
<span class="reserved-syntax">Array</span><span class="plain-syntax"> </span><span class="identifier-syntax">pattern2</span><span class="plain-syntax"> --> </span><span class="constant-syntax">32</span><span class="plain-syntax">; </span><span class="comment-syntax">And another, which stores the best match</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">pcount2</span><span class="plain-syntax">; </span><span class="comment-syntax">so far</span>
<span class="reserved-syntax">Array</span><span class="plain-syntax"> </span><span class="identifier-syntax">line_ttype</span><span class="plain-syntax">-->32; </span><span class="comment-syntax">For storing an analysed grammar line</span>
<span class="reserved-syntax">Array</span><span class="plain-syntax"> </span><span class="identifier-syntax">line_tdata</span><span class="plain-syntax">-->32;</span>
<span class="reserved-syntax">Array</span><span class="plain-syntax"> </span><span class="identifier-syntax">line_token</span><span class="plain-syntax">-->32;</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">nsns</span><span class="plain-syntax">; </span><span class="comment-syntax">Number of special_numbers entered so far</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">params_wanted</span><span class="plain-syntax">; </span><span class="comment-syntax">Number of parameters needed (which may change in parsing)</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">inferfrom</span><span class="plain-syntax">; </span><span class="comment-syntax">The point from which the rest of the command must be inferred</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">inferword</span><span class="plain-syntax">; </span><span class="comment-syntax">And the preposition inferred</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">dont_infer_pronoun</span><span class="plain-syntax">; </span><span class="comment-syntax">Do not infer an "it"</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">dont_infer</span><span class="plain-syntax">; </span><span class="comment-syntax">Another dull flag</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">cobj_flag</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">oops_from</span><span class="plain-syntax">; </span><span class="comment-syntax">The "first mistake" word number</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">saved_oops</span><span class="plain-syntax">; </span><span class="comment-syntax">Used in working this out</span>
<span class="reserved-syntax">Array</span><span class="plain-syntax"> </span><span class="identifier-syntax">oops_workspace</span><span class="plain-syntax"> -> </span><span class="constant-syntax">64</span><span class="plain-syntax">; </span><span class="comment-syntax">Used temporarily by "oops" routine</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">held_back_mode</span><span class="plain-syntax">; </span><span class="comment-syntax">Flag: is there some input from last time</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">hb_wn</span><span class="plain-syntax">; </span><span class="comment-syntax">left over? (And a save value for wn.)</span>
<span class="plain-syntax"> </span><span class="comment-syntax">(Used for full stops and "then".)</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">usual_grammar_after</span><span class="plain-syntax">; </span><span class="comment-syntax">Point from which usual grammar is parsed (it may vary from</span>
<span class="plain-syntax"> </span><span class="comment-syntax">the above if user's routines match multi-word verbs)</span>
</pre>
<p class="commentary firstcommentary"><a id="SP4" class="paragraph-anchor"></a><b>§4. Grammar Token Variables. </b>More globals, but dealing at the level of individual tokens now.
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">PATTERN_NULL</span><span class="plain-syntax"> = </span><span class="constant-syntax">$ffff</span><span class="plain-syntax">; </span><span class="comment-syntax">Entry for a token producing no text</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">found_ttype</span><span class="plain-syntax">; </span><span class="comment-syntax">Used to break up tokens into type</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">found_tdata</span><span class="plain-syntax">; </span><span class="comment-syntax">and data (by AnalyseToken)</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">token_filter</span><span class="plain-syntax">; </span><span class="comment-syntax">For noun filtering by user routines</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">length_of_noun</span><span class="plain-syntax">; </span><span class="comment-syntax">Set by NounDomain to no of words in noun</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">lookahead</span><span class="plain-syntax">; </span><span class="comment-syntax">The token after the one now being matched</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">multi_mode</span><span class="plain-syntax">; </span><span class="comment-syntax">Multiple mode</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">multi_wanted</span><span class="plain-syntax">; </span><span class="comment-syntax">Number of things needed in multitude</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">multi_had</span><span class="plain-syntax">; </span><span class="comment-syntax">Number of things actually found</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">multi_context</span><span class="plain-syntax">; </span><span class="comment-syntax">What token the multi-obj was accepted for</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">indef_type</span><span class="plain-syntax">; </span><span class="comment-syntax">Bit-map holding types of specification</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">indef_wanted</span><span class="plain-syntax">; </span><span class="comment-syntax">Number of items wanted (INDEF_ALL_WANTED for all)</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">INDEF_ALL_WANTED</span><span class="plain-syntax"> = </span><span class="constant-syntax">32767</span><span class="plain-syntax">;</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">indef_guess_p</span><span class="plain-syntax">; </span><span class="comment-syntax">Plural-guessing flag</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">indef_owner</span><span class="plain-syntax">; </span><span class="comment-syntax">Object which must hold these items</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">indef_cases</span><span class="plain-syntax">; </span><span class="comment-syntax">Possible gender and numbers of them</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">indef_possambig</span><span class="plain-syntax">; </span><span class="comment-syntax">Has a possibly dangerous assumption</span>
<span class="plain-syntax"> </span><span class="comment-syntax">been made about meaning of a descriptor?</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">indef_nspec_at</span><span class="plain-syntax">; </span><span class="comment-syntax">Word at which a number like "two" was parsed</span>
<span class="plain-syntax"> </span><span class="comment-syntax">(for backtracking)</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">allow_plurals</span><span class="plain-syntax">; </span><span class="comment-syntax">Whether plurals presently allowed or not</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">take_all_rule</span><span class="plain-syntax">; </span><span class="comment-syntax">Slightly different rules apply to "take all" than other uses</span>
<span class="plain-syntax"> </span><span class="comment-syntax">of multiple objects, to make adjudication produce more</span>
<span class="plain-syntax"> </span><span class="comment-syntax">pragmatically useful results</span>
<span class="plain-syntax"> </span><span class="comment-syntax">(Not a flag: possible values 0, 1, 2)</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">dict_flags_of_noun</span><span class="plain-syntax">; </span><span class="comment-syntax">Of the noun currently being parsed</span>
<span class="plain-syntax"> </span><span class="comment-syntax">(a bitmap in #dict_par1 format)</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">pronoun__word</span><span class="plain-syntax">; </span><span class="comment-syntax">Saved value</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">pronoun__obj</span><span class="plain-syntax">; </span><span class="comment-syntax">Saved value</span>
<span class="reserved-syntax">Constant</span><span class="plain-syntax"> </span><span class="identifier-syntax">comma_word</span><span class="plain-syntax"> = </span><span class="character-syntax">'comma,'</span><span class="plain-syntax">; </span><span class="comment-syntax">An "untypeable word" used to substitute</span>
<span class="plain-syntax"> </span><span class="comment-syntax">for commas in parse buffers</span>
</pre>
<p class="commentary firstcommentary"><a id="SP5" class="paragraph-anchor"></a><b>§5. Match List Variables. </b>The most difficult tokens to match are those which refer to objects, since
there is such a variety of names which can be given to any individual object,
and we don't of course know which object or objects are meant. We store the
possibilities (up to <span class="extract"><span class="extract-syntax">MATCH_LIST_WORDS</span></span>, anyway) in a data structure called the match list.
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="reserved-syntax">Array</span><span class="plain-syntax"> </span><span class="identifier-syntax">match_list</span><span class="plain-syntax"> --> </span><span class="identifier-syntax">MATCH_LIST_WORDS</span><span class="plain-syntax">; </span><span class="comment-syntax">An array of matched objects so far</span>
<span class="reserved-syntax">Array</span><span class="plain-syntax"> </span><span class="identifier-syntax">match_classes</span><span class="plain-syntax"> --> </span><span class="identifier-syntax">MATCH_LIST_WORDS</span><span class="plain-syntax">; </span><span class="comment-syntax">An array of equivalence classes for them</span>
<span class="reserved-syntax">Array</span><span class="plain-syntax"> </span><span class="identifier-syntax">match_scores</span><span class="plain-syntax"> --> </span><span class="identifier-syntax">MATCH_LIST_WORDS</span><span class="plain-syntax">; </span><span class="comment-syntax">An array of match scores for them</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">number_matched</span><span class="plain-syntax">; </span><span class="comment-syntax">How many items in it? (0 means none)</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">number_of_classes</span><span class="plain-syntax">; </span><span class="comment-syntax">How many equivalence classes?</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">match_length</span><span class="plain-syntax">; </span><span class="comment-syntax">How many words long are these matches?</span>
<span class="identifier-syntax">Global</span><span class="plain-syntax"> </span><span class="identifier-syntax">match_from</span><span class="plain-syntax">; </span><span class="comment-syntax">At what word of the input do they begin?</span>
</pre>
<p class="commentary firstcommentary"><a id="SP6" class="paragraph-anchor"></a><b>§6. Words. </b>The player's command is broken down into a numbered sequence of words, which
break at spaces or certain punctuation (see the DM4). The numbering runs
upwards from 1 to <span class="extract"><span class="extract-syntax">WordCount()</span></span>. The following utility routines provide
access to words in the current command; because buffers have different
definitions in Z and Glulx, so these routines must vary also.
</p>
<p class="commentary">The actual text of each word is stored as a sequence of ZSCII values in
a <span class="extract"><span class="extract-syntax">-></span></span> (byte) array, with address <span class="extract"><span class="extract-syntax">WordAddress(x)</span></span> and length <span class="extract"><span class="extract-syntax">WordLength(x)</span></span>.
</p>
<p class="commentary">We picture the command as a stream of words to be read one at a time, with
the global variable <span class="extract"><span class="extract-syntax">wn</span></span> being the "current word" marker. <span class="extract"><span class="extract-syntax">NextWord</span></span>, which
takes no arguments, returns:
</p>
<ul class="items"><li>(a) 0 if the word at <span class="extract"><span class="extract-syntax">wn</span></span> is unrecognised by the dictionary or <span class="extract"><span class="extract-syntax">wn</span></span> is out
of range,
</li><li>(b) <span class="extract"><span class="extract-syntax">comma_word</span></span> if the word was a comma,
</li><li>(c) <span class="extract"><span class="extract-syntax">THEN1__WD</span></span> if it was a full stop (because of the Infocom tradition that
a full stop abbreviates for the word "then": e.g., TAKE BOX. EAST was read
as two commands in succession),
</li><li>(d) or the dictionary address if the word was recognised.
</li></ul>
<p class="commentary">The current word marker <span class="extract"><span class="extract-syntax">wn</span></span> is always advanced.
</p>
<p class="commentary"><span class="extract"><span class="extract-syntax">NextWordStopped</span></span> does the same, but returns \(-1\) when <span class="extract"><span class="extract-syntax">wn</span></span> is out of range
(e.g., by having advanced past the last word in the command).
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax">#</span><span class="identifier-syntax">Ifdef</span><span class="plain-syntax"> </span><span class="identifier-syntax">TARGET_ZCODE</span><span class="plain-syntax">;</span>
<span class="plain-syntax">[ </span><span class="identifier-syntax">WordCount</span><span class="plain-syntax">; </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">parse</span><span class="plain-syntax">->1; ];</span>
<span class="plain-syntax">[ </span><span class="identifier-syntax">WordAddress</span><span class="plain-syntax"> </span><span class="identifier-syntax">wordnum</span><span class="plain-syntax">; </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">buffer</span><span class="plain-syntax"> + </span><span class="identifier-syntax">parse</span><span class="plain-syntax">->(</span><span class="identifier-syntax">wordnum</span><span class="plain-syntax">*4+1); ];</span>
<span class="plain-syntax">[ </span><span class="identifier-syntax">WordLength</span><span class="plain-syntax"> </span><span class="identifier-syntax">wordnum</span><span class="plain-syntax">; </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">parse</span><span class="plain-syntax">->(</span><span class="identifier-syntax">wordnum</span><span class="plain-syntax">*4); ];</span>
<span class="plain-syntax">#</span><span class="identifier-syntax">Ifnot</span><span class="plain-syntax">;</span>
<span class="plain-syntax">[ </span><span class="identifier-syntax">WordCount</span><span class="plain-syntax">; </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">parse</span><span class="plain-syntax">-->0; ];</span>
<span class="plain-syntax">[ </span><span class="identifier-syntax">WordAddress</span><span class="plain-syntax"> </span><span class="identifier-syntax">wordnum</span><span class="plain-syntax">; </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">buffer</span><span class="plain-syntax"> + </span><span class="identifier-syntax">parse</span><span class="plain-syntax">-->(</span><span class="identifier-syntax">wordnum</span><span class="plain-syntax">*3); ];</span>
<span class="plain-syntax">[ </span><span class="identifier-syntax">WordLength</span><span class="plain-syntax"> </span><span class="identifier-syntax">wordnum</span><span class="plain-syntax">; </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">parse</span><span class="plain-syntax">-->(</span><span class="identifier-syntax">wordnum</span><span class="plain-syntax">*3 - </span><span class="constant-syntax">1</span><span class="plain-syntax">); ];</span>
<span class="plain-syntax">#</span><span class="identifier-syntax">Endif</span><span class="plain-syntax">;</span>
<span class="plain-syntax">[ </span><span class="identifier-syntax">WordFrom</span><span class="plain-syntax"> </span><span class="identifier-syntax">w</span><span class="plain-syntax"> </span><span class="identifier-syntax">p</span><span class="plain-syntax"> </span><span class="identifier-syntax">i</span><span class="plain-syntax"> </span><span class="identifier-syntax">j</span><span class="plain-syntax"> </span><span class="identifier-syntax">wc</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifdef</span><span class="plain-syntax"> </span><span class="identifier-syntax">TARGET_ZCODE</span><span class="plain-syntax">; </span><span class="identifier-syntax">wc</span><span class="plain-syntax"> = </span><span class="identifier-syntax">p</span><span class="plain-syntax">->1; </span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">w</span><span class="plain-syntax">*2-1;</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifnot</span><span class="plain-syntax">; </span><span class="identifier-syntax">wc</span><span class="plain-syntax"> = </span><span class="identifier-syntax">p</span><span class="plain-syntax">-->0; </span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">w</span><span class="plain-syntax">*3-2; #</span><span class="identifier-syntax">Endif</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> ((</span><span class="identifier-syntax">w</span><span class="plain-syntax"> < </span><span class="constant-syntax">1</span><span class="plain-syntax">) || (</span><span class="identifier-syntax">w</span><span class="plain-syntax"> > </span><span class="identifier-syntax">wc</span><span class="plain-syntax">)) </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">j</span><span class="plain-syntax"> = </span><span class="identifier-syntax">p</span><span class="plain-syntax">--></span><span class="identifier-syntax">i</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">j</span><span class="plain-syntax"> == </span><span class="character-syntax">',//'</span><span class="plain-syntax">) </span><span class="identifier-syntax">j</span><span class="plain-syntax"> = </span><span class="identifier-syntax">comma_word</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">j</span><span class="plain-syntax"> == </span><span class="character-syntax">'.//'</span><span class="plain-syntax">) </span><span class="identifier-syntax">j</span><span class="plain-syntax"> = </span><span class="identifier-syntax">THEN1__WD</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">j</span><span class="plain-syntax">;</span>
<span class="plain-syntax">];</span>
<span class="plain-syntax">[ </span><span class="identifier-syntax">NextWord</span><span class="plain-syntax"> </span><span class="identifier-syntax">i</span><span class="plain-syntax"> </span><span class="identifier-syntax">j</span><span class="plain-syntax"> </span><span class="identifier-syntax">wc</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifdef</span><span class="plain-syntax"> </span><span class="identifier-syntax">TARGET_ZCODE</span><span class="plain-syntax">; </span><span class="identifier-syntax">wc</span><span class="plain-syntax"> = </span><span class="identifier-syntax">parse</span><span class="plain-syntax">->1; </span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">wn</span><span class="plain-syntax">*2-1;</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifnot</span><span class="plain-syntax">; </span><span class="identifier-syntax">wc</span><span class="plain-syntax"> = </span><span class="identifier-syntax">parse</span><span class="plain-syntax">-->0; </span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">wn</span><span class="plain-syntax">*3-2; #</span><span class="identifier-syntax">Endif</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">wn</span><span class="plain-syntax">++;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> ((</span><span class="identifier-syntax">wn</span><span class="plain-syntax"> < </span><span class="constant-syntax">2</span><span class="plain-syntax">) || (</span><span class="identifier-syntax">wn</span><span class="plain-syntax"> > </span><span class="identifier-syntax">wc</span><span class="plain-syntax">+1)) </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">j</span><span class="plain-syntax"> = </span><span class="identifier-syntax">parse</span><span class="plain-syntax">--></span><span class="identifier-syntax">i</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">j</span><span class="plain-syntax"> == </span><span class="character-syntax">',//'</span><span class="plain-syntax">) </span><span class="identifier-syntax">j</span><span class="plain-syntax"> = </span><span class="identifier-syntax">comma_word</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">j</span><span class="plain-syntax"> == </span><span class="character-syntax">'.//'</span><span class="plain-syntax">) </span><span class="identifier-syntax">j</span><span class="plain-syntax"> = </span><span class="identifier-syntax">THEN1__WD</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">j</span><span class="plain-syntax">;</span>
<span class="plain-syntax">];</span>
<span class="plain-syntax">[ </span><span class="identifier-syntax">NextWordStopped</span><span class="plain-syntax"> </span><span class="identifier-syntax">wc</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifdef</span><span class="plain-syntax"> </span><span class="identifier-syntax">TARGET_ZCODE</span><span class="plain-syntax">; </span><span class="identifier-syntax">wc</span><span class="plain-syntax"> = </span><span class="identifier-syntax">parse</span><span class="plain-syntax">->1; #</span><span class="identifier-syntax">Ifnot</span><span class="plain-syntax">; </span><span class="identifier-syntax">wc</span><span class="plain-syntax"> = </span><span class="identifier-syntax">parse</span><span class="plain-syntax">-->0; #</span><span class="identifier-syntax">Endif</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> ((</span><span class="identifier-syntax">wn</span><span class="plain-syntax"> < </span><span class="constant-syntax">1</span><span class="plain-syntax">) || (</span><span class="identifier-syntax">wn</span><span class="plain-syntax"> > </span><span class="identifier-syntax">wc</span><span class="plain-syntax">)) { </span><span class="identifier-syntax">wn</span><span class="plain-syntax">++; </span><span class="reserved-syntax">return</span><span class="plain-syntax"> -1; }</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">NextWord</span><span class="plain-syntax">();</span>
<span class="plain-syntax">];</span>
</pre>
<p class="commentary firstcommentary"><a id="SP7" class="paragraph-anchor"></a><b>§7. Snippets. </b>Although the idea is arguably implicit in I6, the formal concept of
"snippet" is new in I7. A snippet is a value which represents a word
range in the command most recently typed by the player. These words number
consecutively upwards from 1, as noted above. The correspondence between
\((w_1, w_2)\), the word range, and \(V\), the number used to represent it as
an I6 value, is:
$$ V = 100w_1 + (w_2-w_1+1) $$
so that the remainder mod 100 is the number of words in the range. We
require that \(1\leq w_1\leq w_2\leq N\), where \(N\) is the number of words in
the current player's command. The entire command is therefore represented by:
$$ C = 100 + N $$
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax">[ </span><span class="identifier-syntax">PrintSnippet</span><span class="plain-syntax"> </span><span class="identifier-syntax">snip</span><span class="plain-syntax"> </span><span class="identifier-syntax">from</span><span class="plain-syntax"> </span><span class="reserved-syntax">to</span><span class="plain-syntax"> </span><span class="identifier-syntax">i</span><span class="plain-syntax"> </span><span class="identifier-syntax">w1</span><span class="plain-syntax"> </span><span class="identifier-syntax">w2</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">w1</span><span class="plain-syntax"> = </span><span class="identifier-syntax">snip</span><span class="plain-syntax">/100; </span><span class="identifier-syntax">w2</span><span class="plain-syntax"> = </span><span class="identifier-syntax">w1</span><span class="plain-syntax"> + (</span><span class="identifier-syntax">snip</span><span class="plain-syntax">%100) - </span><span class="constant-syntax">1</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> ((</span><span class="identifier-syntax">w2</span><span class="plain-syntax"><</span><span class="identifier-syntax">w1</span><span class="plain-syntax">) || (</span><span class="identifier-syntax">w1</span><span class="plain-syntax"><1) || (</span><span class="identifier-syntax">w2</span><span class="plain-syntax">></span><span class="identifier-syntax">WordCount</span><span class="plain-syntax">())) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> ((</span><span class="identifier-syntax">w1</span><span class="plain-syntax"> == </span><span class="constant-syntax">1</span><span class="plain-syntax">) && (</span><span class="identifier-syntax">w2</span><span class="plain-syntax"> == </span><span class="constant-syntax">0</span><span class="plain-syntax">)) </span><span class="reserved-syntax">rfalse</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">RunTimeProblem</span><span class="plain-syntax">(</span><span class="identifier-syntax">RTP_SAYINVALIDSNIPPET</span><span class="plain-syntax">, </span><span class="identifier-syntax">w1</span><span class="plain-syntax">, </span><span class="identifier-syntax">w2</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">from</span><span class="plain-syntax"> = </span><span class="identifier-syntax">WordAddress</span><span class="plain-syntax">(</span><span class="identifier-syntax">w1</span><span class="plain-syntax">); </span><span class="reserved-syntax">to</span><span class="plain-syntax"> = </span><span class="identifier-syntax">WordAddress</span><span class="plain-syntax">(</span><span class="identifier-syntax">w2</span><span class="plain-syntax">) + </span><span class="identifier-syntax">WordLength</span><span class="plain-syntax">(</span><span class="identifier-syntax">w2</span><span class="plain-syntax">) - </span><span class="constant-syntax">1</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">for</span><span class="plain-syntax"> (</span><span class="identifier-syntax">i</span><span class="plain-syntax">=</span><span class="identifier-syntax">from</span><span class="plain-syntax">: </span><span class="identifier-syntax">i</span><span class="plain-syntax"><=</span><span class="reserved-syntax">to</span><span class="plain-syntax">: </span><span class="identifier-syntax">i</span><span class="plain-syntax">++) </span><span class="reserved-syntax">print</span><span class="plain-syntax"> (</span><span class="identifier-syntax">char</span><span class="plain-syntax">) </span><span class="identifier-syntax">i</span><span class="plain-syntax">->0;</span>
<span class="plain-syntax">];</span>
<span class="plain-syntax">[ </span><span class="identifier-syntax">SpliceSnippet</span><span class="plain-syntax"> </span><span class="identifier-syntax">snip</span><span class="plain-syntax"> </span><span class="identifier-syntax">t</span><span class="plain-syntax"> </span><span class="identifier-syntax">i</span><span class="plain-syntax"> </span><span class="identifier-syntax">w1</span><span class="plain-syntax"> </span><span class="identifier-syntax">w2</span><span class="plain-syntax"> </span><span class="identifier-syntax">nextw</span><span class="plain-syntax"> </span><span class="identifier-syntax">at</span><span class="plain-syntax"> </span><span class="identifier-syntax">endsnippet</span><span class="plain-syntax"> </span><span class="identifier-syntax">newlen</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">w1</span><span class="plain-syntax"> = </span><span class="identifier-syntax">snip</span><span class="plain-syntax">/100; </span><span class="identifier-syntax">w2</span><span class="plain-syntax"> = </span><span class="identifier-syntax">w1</span><span class="plain-syntax"> + (</span><span class="identifier-syntax">snip</span><span class="plain-syntax">%100) - </span><span class="constant-syntax">1</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> ((</span><span class="identifier-syntax">w2</span><span class="plain-syntax"><</span><span class="identifier-syntax">w1</span><span class="plain-syntax">) || (</span><span class="identifier-syntax">w1</span><span class="plain-syntax"><1)) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> ((</span><span class="identifier-syntax">w1</span><span class="plain-syntax"> == </span><span class="constant-syntax">1</span><span class="plain-syntax">) && (</span><span class="identifier-syntax">w2</span><span class="plain-syntax"> == </span><span class="constant-syntax">0</span><span class="plain-syntax">)) </span><span class="reserved-syntax">return</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">RunTimeProblem</span><span class="plain-syntax">(</span><span class="identifier-syntax">RTP_SPLICEINVALIDSNIPPET</span><span class="plain-syntax">, </span><span class="identifier-syntax">w1</span><span class="plain-syntax">, </span><span class="identifier-syntax">w2</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> @</span><span class="identifier-syntax">push</span><span class="plain-syntax"> </span><span class="identifier-syntax">say__p</span><span class="plain-syntax">; @</span><span class="identifier-syntax">push</span><span class="plain-syntax"> </span><span class="identifier-syntax">say__pc</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nextw</span><span class="plain-syntax"> = </span><span class="identifier-syntax">w2</span><span class="plain-syntax"> + </span><span class="constant-syntax">1</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">at</span><span class="plain-syntax"> = </span><span class="identifier-syntax">WordAddress</span><span class="plain-syntax">(</span><span class="identifier-syntax">w1</span><span class="plain-syntax">) - </span><span class="identifier-syntax">buffer</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">nextw</span><span class="plain-syntax"> <= </span><span class="identifier-syntax">WordCount</span><span class="plain-syntax">()) </span><span class="identifier-syntax">endsnippet</span><span class="plain-syntax"> = </span><span class="constant-syntax">100</span><span class="plain-syntax">*</span><span class="identifier-syntax">nextw</span><span class="plain-syntax"> + (</span><span class="identifier-syntax">WordCount</span><span class="plain-syntax">() - </span><span class="identifier-syntax">nextw</span><span class="plain-syntax"> + </span><span class="constant-syntax">1</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">buffer2</span><span class="plain-syntax">-->0 = </span><span class="constant-syntax">120</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">newlen</span><span class="plain-syntax"> = </span><span class="identifier-syntax">VM_PrintToBuffer</span><span class="plain-syntax">(</span><span class="identifier-syntax">buffer2</span><span class="plain-syntax">, </span><span class="constant-syntax">120</span><span class="plain-syntax">, </span><span class="identifier-syntax">SpliceSnippet__TextPrinter</span><span class="plain-syntax">, </span><span class="identifier-syntax">t</span><span class="plain-syntax">, </span><span class="identifier-syntax">endsnippet</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">for</span><span class="plain-syntax"> (</span><span class="identifier-syntax">i</span><span class="plain-syntax">=0: (</span><span class="identifier-syntax">i</span><span class="plain-syntax"><</span><span class="identifier-syntax">newlen</span><span class="plain-syntax">) && (</span><span class="identifier-syntax">at</span><span class="plain-syntax">+</span><span class="identifier-syntax">i</span><span class="plain-syntax"><120): </span><span class="identifier-syntax">i</span><span class="plain-syntax">++) </span><span class="identifier-syntax">buffer</span><span class="plain-syntax">->(</span><span class="identifier-syntax">at</span><span class="plain-syntax">+</span><span class="identifier-syntax">i</span><span class="plain-syntax">) = </span><span class="identifier-syntax">buffer2</span><span class="plain-syntax">->(</span><span class="identifier-syntax">WORDSIZE</span><span class="plain-syntax">+</span><span class="identifier-syntax">i</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifdef</span><span class="plain-syntax"> </span><span class="identifier-syntax">TARGET_ZCODE</span><span class="plain-syntax">; </span><span class="identifier-syntax">buffer</span><span class="plain-syntax">->1 = </span><span class="identifier-syntax">at</span><span class="plain-syntax">+</span><span class="identifier-syntax">i</span><span class="plain-syntax">; #</span><span class="identifier-syntax">ifnot</span><span class="plain-syntax">; </span><span class="identifier-syntax">buffer</span><span class="plain-syntax">-->0 = </span><span class="identifier-syntax">at</span><span class="plain-syntax">+</span><span class="identifier-syntax">i</span><span class="plain-syntax">; #</span><span class="identifier-syntax">endif</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">for</span><span class="plain-syntax"> (:</span><span class="identifier-syntax">at</span><span class="plain-syntax">+</span><span class="identifier-syntax">i</span><span class="plain-syntax"><120:</span><span class="identifier-syntax">i</span><span class="plain-syntax">++) </span><span class="identifier-syntax">buffer</span><span class="plain-syntax">->(</span><span class="identifier-syntax">at</span><span class="plain-syntax">+</span><span class="identifier-syntax">i</span><span class="plain-syntax">) = </span><span class="character-syntax">' '</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">VM_Tokenise</span><span class="plain-syntax">(</span><span class="identifier-syntax">buffer</span><span class="plain-syntax">, </span><span class="identifier-syntax">parse</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">players_command</span><span class="plain-syntax"> = </span><span class="constant-syntax">100</span><span class="plain-syntax"> + </span><span class="identifier-syntax">WordCount</span><span class="plain-syntax">();</span>
<span class="plain-syntax"> @</span><span class="identifier-syntax">pull</span><span class="plain-syntax"> </span><span class="identifier-syntax">say__pc</span><span class="plain-syntax">; @</span><span class="identifier-syntax">pull</span><span class="plain-syntax"> </span><span class="identifier-syntax">say__p</span><span class="plain-syntax">;</span>
<span class="plain-syntax">];</span>
<span class="plain-syntax">[ </span><span class="identifier-syntax">SpliceSnippet__TextPrinter</span><span class="plain-syntax"> </span><span class="identifier-syntax">t</span><span class="plain-syntax"> </span><span class="identifier-syntax">endsnippet</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">TEXT_TY_Say</span><span class="plain-syntax">(</span><span class="identifier-syntax">t</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">endsnippet</span><span class="plain-syntax">) { </span><span class="reserved-syntax">print</span><span class="plain-syntax"> </span><span class="string-syntax">" "</span><span class="plain-syntax">; </span><span class="identifier-syntax">PrintSnippet</span><span class="plain-syntax">(</span><span class="identifier-syntax">endsnippet</span><span class="plain-syntax">); }</span>
<span class="plain-syntax">];</span>
<span class="plain-syntax">[ </span><span class="identifier-syntax">SnippetIncludes</span><span class="plain-syntax"> </span><span class="identifier-syntax">test</span><span class="plain-syntax"> </span><span class="identifier-syntax">snippet</span><span class="plain-syntax"> </span><span class="identifier-syntax">w1</span><span class="plain-syntax"> </span><span class="identifier-syntax">w2</span><span class="plain-syntax"> </span><span class="identifier-syntax">wlen</span><span class="plain-syntax"> </span><span class="identifier-syntax">i</span><span class="plain-syntax"> </span><span class="identifier-syntax">j</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">w1</span><span class="plain-syntax"> = </span><span class="identifier-syntax">snippet</span><span class="plain-syntax">/100; </span><span class="identifier-syntax">w2</span><span class="plain-syntax"> = </span><span class="identifier-syntax">w1</span><span class="plain-syntax"> + (</span><span class="identifier-syntax">snippet</span><span class="plain-syntax">%100) - </span><span class="constant-syntax">1</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> ((</span><span class="identifier-syntax">w2</span><span class="plain-syntax"><</span><span class="identifier-syntax">w1</span><span class="plain-syntax">) || (</span><span class="identifier-syntax">w1</span><span class="plain-syntax"><1)) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> ((</span><span class="identifier-syntax">w1</span><span class="plain-syntax"> == </span><span class="constant-syntax">1</span><span class="plain-syntax">) && (</span><span class="identifier-syntax">w2</span><span class="plain-syntax"> == </span><span class="constant-syntax">0</span><span class="plain-syntax">)) </span><span class="reserved-syntax">rfalse</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">RunTimeProblem</span><span class="plain-syntax">(</span><span class="identifier-syntax">RTP_INCLUDEINVALIDSNIPPET</span><span class="plain-syntax">, </span><span class="identifier-syntax">w1</span><span class="plain-syntax">, </span><span class="identifier-syntax">w2</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="reserved-syntax">metaclass</span><span class="plain-syntax">(</span><span class="identifier-syntax">test</span><span class="plain-syntax">) == </span><span class="identifier-syntax">Routine</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">wlen</span><span class="plain-syntax"> = </span><span class="identifier-syntax">snippet</span><span class="plain-syntax">%100;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">for</span><span class="plain-syntax"> (</span><span class="identifier-syntax">i</span><span class="plain-syntax">=</span><span class="identifier-syntax">w1</span><span class="plain-syntax">, </span><span class="identifier-syntax">j</span><span class="plain-syntax">=</span><span class="identifier-syntax">wlen</span><span class="plain-syntax">: </span><span class="identifier-syntax">j</span><span class="plain-syntax">>0: </span><span class="identifier-syntax">i</span><span class="plain-syntax">++, </span><span class="identifier-syntax">j</span><span class="plain-syntax">--) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (((</span><span class="identifier-syntax">test</span><span class="plain-syntax">)(</span><span class="identifier-syntax">i</span><span class="plain-syntax">, </span><span class="constant-syntax">0</span><span class="plain-syntax">)) ~= </span><span class="identifier-syntax">GPR_FAIL</span><span class="plain-syntax">) </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">i</span><span class="plain-syntax">*100+</span><span class="identifier-syntax">wn</span><span class="plain-syntax">-</span><span class="identifier-syntax">i</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">rfalse</span><span class="plain-syntax">;</span>
<span class="plain-syntax">];</span>
<span class="plain-syntax">[ </span><span class="identifier-syntax">SnippetMatches</span><span class="plain-syntax"> </span><span class="identifier-syntax">snippet</span><span class="plain-syntax"> </span><span class="identifier-syntax">topic_gpr</span><span class="plain-syntax"> </span><span class="identifier-syntax">rv</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">wn</span><span class="plain-syntax">=1;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">topic_gpr</span><span class="plain-syntax"> == </span><span class="constant-syntax">0</span><span class="plain-syntax">) </span><span class="reserved-syntax">rfalse</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="reserved-syntax">metaclass</span><span class="plain-syntax">(</span><span class="identifier-syntax">topic_gpr</span><span class="plain-syntax">) == </span><span class="identifier-syntax">Routine</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">rv</span><span class="plain-syntax"> = (</span><span class="identifier-syntax">topic_gpr</span><span class="plain-syntax">)(</span><span class="identifier-syntax">snippet</span><span class="plain-syntax">/100, </span><span class="identifier-syntax">snippet</span><span class="plain-syntax">%100);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">rv</span><span class="plain-syntax"> ~= </span><span class="identifier-syntax">GPR_FAIL</span><span class="plain-syntax">) </span><span class="reserved-syntax">rtrue</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">rfalse</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">RunTimeProblem</span><span class="plain-syntax">(</span><span class="identifier-syntax">RTP_BADTOPIC</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">rfalse</span><span class="plain-syntax">;</span>
<span class="plain-syntax">];</span>
</pre>
<p class="commentary firstcommentary"><a id="SP8" class="paragraph-anchor"></a><b>§8. Unpacking Grammar Lines. </b>Grammar lines are sequences of tokens in an array built into the story file,
but in a format which differs depending on the virtual machine in use, so
the following code unpacks the data into more convenient if larger arrays
which are VM-independent.
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax">[ </span><span class="identifier-syntax">UnpackGrammarLine</span><span class="plain-syntax"> </span><span class="identifier-syntax">line_address</span><span class="plain-syntax"> </span><span class="identifier-syntax">i</span><span class="plain-syntax"> </span><span class="identifier-syntax">size</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">for</span><span class="plain-syntax"> (</span><span class="identifier-syntax">i</span><span class="plain-syntax">=0 : </span><span class="identifier-syntax">i</span><span class="plain-syntax"><32 : </span><span class="identifier-syntax">i</span><span class="plain-syntax">++) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">line_token</span><span class="plain-syntax">--></span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">ENDIT_TOKEN</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">line_ttype</span><span class="plain-syntax">--></span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">ELEMENTARY_TT</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">line_tdata</span><span class="plain-syntax">--></span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">ENDIT_TOKEN</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax">#</span><span class="identifier-syntax">Ifdef</span><span class="plain-syntax"> </span><span class="identifier-syntax">TARGET_ZCODE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">action_to_be</span><span class="plain-syntax"> = </span><span class="constant-syntax">256</span><span class="plain-syntax">*(</span><span class="identifier-syntax">line_address</span><span class="plain-syntax">->0) + </span><span class="identifier-syntax">line_address</span><span class="plain-syntax">->1;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">action_reversed</span><span class="plain-syntax"> = ((</span><span class="identifier-syntax">action_to_be</span><span class="plain-syntax"> & </span><span class="constant-syntax">$400</span><span class="plain-syntax">) ~= </span><span class="constant-syntax">0</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">action_to_be</span><span class="plain-syntax"> = </span><span class="identifier-syntax">action_to_be</span><span class="plain-syntax"> & </span><span class="constant-syntax">$3ff</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">line_address</span><span class="plain-syntax">--;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">size</span><span class="plain-syntax"> = </span><span class="constant-syntax">3</span><span class="plain-syntax">;</span>
<span class="plain-syntax">#</span><span class="identifier-syntax">Ifnot</span><span class="plain-syntax">; </span><span class="comment-syntax">GLULX</span>
<span class="plain-syntax"> @</span><span class="identifier-syntax">aloads</span><span class="plain-syntax"> </span><span class="identifier-syntax">line_address</span><span class="plain-syntax"> </span><span class="constant-syntax">0</span><span class="plain-syntax"> </span><span class="identifier-syntax">action_to_be</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">action_reversed</span><span class="plain-syntax"> = (((</span><span class="identifier-syntax">line_address</span><span class="plain-syntax">->2) & </span><span class="constant-syntax">1</span><span class="plain-syntax">) ~= </span><span class="constant-syntax">0</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">line_address</span><span class="plain-syntax"> = </span><span class="identifier-syntax">line_address</span><span class="plain-syntax"> - </span><span class="constant-syntax">2</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">size</span><span class="plain-syntax"> = </span><span class="constant-syntax">5</span><span class="plain-syntax">;</span>
<span class="plain-syntax">#</span><span class="identifier-syntax">Endif</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">params_wanted</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">for</span><span class="plain-syntax"> (</span><span class="identifier-syntax">i</span><span class="plain-syntax">=0 : : </span><span class="identifier-syntax">i</span><span class="plain-syntax">++) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">line_address</span><span class="plain-syntax"> = </span><span class="identifier-syntax">line_address</span><span class="plain-syntax"> + </span><span class="identifier-syntax">size</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">line_address</span><span class="plain-syntax">->0 == </span><span class="identifier-syntax">ENDIT_TOKEN</span><span class="plain-syntax">) </span><span class="reserved-syntax">break</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">line_token</span><span class="plain-syntax">--></span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">line_address</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">AnalyseToken</span><span class="plain-syntax">(</span><span class="identifier-syntax">line_address</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">found_ttype</span><span class="plain-syntax"> ~= </span><span class="identifier-syntax">PREPOSITION_TT</span><span class="plain-syntax">) </span><span class="identifier-syntax">params_wanted</span><span class="plain-syntax">++;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">line_ttype</span><span class="plain-syntax">--></span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">found_ttype</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">line_tdata</span><span class="plain-syntax">--></span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">found_tdata</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">line_address</span><span class="plain-syntax"> + </span><span class="constant-syntax">1</span><span class="plain-syntax">;</span>
<span class="plain-syntax">];</span>
<span class="plain-syntax">[ </span><span class="identifier-syntax">AnalyseToken</span><span class="plain-syntax"> </span><span class="identifier-syntax">token</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">token</span><span class="plain-syntax"> == </span><span class="identifier-syntax">ENDIT_TOKEN</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">found_ttype</span><span class="plain-syntax"> = </span><span class="identifier-syntax">ELEMENTARY_TT</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">found_tdata</span><span class="plain-syntax"> = </span><span class="identifier-syntax">ENDIT_TOKEN</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">return</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">found_ttype</span><span class="plain-syntax"> = (</span><span class="identifier-syntax">token</span><span class="plain-syntax">->0) & </span><span class="constant-syntax">$$1111</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">found_tdata</span><span class="plain-syntax"> = (</span><span class="identifier-syntax">token</span><span class="plain-syntax">+1)-->0;</span>
<span class="plain-syntax">];</span>
</pre>
<p class="commentary firstcommentary"><a id="SP9" class="paragraph-anchor"></a><b>§9. Keyboard Primitive. </b>This is the primitive routine to read from the keyboard: it usually delegates
this to a routine specific to the virtual machine being used, but sometimes
uses a hacked version to allow TEST commands to work. (When a TEST is running,
the text in the walk-through provided is fed into the buffer as if it had
been typed at the keyboard.)
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax">[ </span><span class="identifier-syntax">KeyboardPrimitive</span><span class="plain-syntax"> </span><span class="identifier-syntax">a_buffer</span><span class="plain-syntax"> </span><span class="identifier-syntax">a_table</span><span class="plain-syntax">;</span>
<span class="plain-syntax">#</span><span class="identifier-syntax">Ifdef</span><span class="plain-syntax"> </span><span class="identifier-syntax">DEBUG</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">TestKeyboardPrimitive</span><span class="plain-syntax">(</span><span class="identifier-syntax">a_buffer</span><span class="plain-syntax">, </span><span class="identifier-syntax">a_table</span><span class="plain-syntax">);</span>
<span class="plain-syntax">#</span><span class="identifier-syntax">Endif</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">VM_ReadKeyboard</span><span class="plain-syntax">(</span><span class="identifier-syntax">a_buffer</span><span class="plain-syntax">, </span><span class="identifier-syntax">a_table</span><span class="plain-syntax">);</span>
<span class="plain-syntax">];</span>
</pre>
<p class="commentary firstcommentary"><a id="SP10" class="paragraph-anchor"></a><b>§10. Reading the Command. </b>The <span class="extract"><span class="extract-syntax">Keyboard</span></span> routine actually receives the player's words, putting the
words in <span class="extract"><span class="extract-syntax">a_buffer</span></span> and their dictionary addresses in <span class="extract"><span class="extract-syntax">a_table</span></span>. It is
assumed that the table is the same one on each (standard) call. Much
of the code handles the OOPS and UNDO commands, which are not actions and
do not pass through the rest of the parser. The undo state is saved —
it is essentially an internal saved game, in the VM interpreter's memory
rather than in an external file — and note that this is therefore also
where execution picks up if an UNDO has been typed. Since UNDO recreates
the former machine state perfectly, it might seem impossible to tell that
an UNDO had occurred, but in fact the VM passes information back in the
form of a return code from the relevant instruction, and this allows us
to detect an undo. (We deal with it by printing the current location and
asking another command.)
</p>
<p class="commentary"><span class="extract"><span class="extract-syntax">Keyboard</span></span> can also be used by miscellaneous routines in the game to ask
yes/no questions and the like, without invoking the rest of the parser.
</p>
<p class="commentary">The return value is the number of words typed.
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax">[ </span><span class="identifier-syntax">Keyboard</span><span class="plain-syntax"> </span><span class="identifier-syntax">a_buffer</span><span class="plain-syntax"> </span><span class="identifier-syntax">a_table</span><span class="plain-syntax"> </span><span class="identifier-syntax">nw</span><span class="plain-syntax"> </span><span class="identifier-syntax">i</span><span class="plain-syntax"> </span><span class="identifier-syntax">w</span><span class="plain-syntax"> </span><span class="identifier-syntax">w2</span><span class="plain-syntax"> </span><span class="identifier-syntax">x1</span><span class="plain-syntax"> </span><span class="identifier-syntax">x2</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">sline1</span><span class="plain-syntax"> = </span><span class="identifier-syntax">score</span><span class="plain-syntax">; </span><span class="identifier-syntax">sline2</span><span class="plain-syntax"> = </span><span class="identifier-syntax">turns</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">while</span><span class="plain-syntax"> (</span><span class="reserved-syntax">true</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="comment-syntax">Save the start of the buffer, in case "oops" needs to restore it</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">for</span><span class="plain-syntax"> (</span><span class="identifier-syntax">i</span><span class="plain-syntax">=0 : </span><span class="identifier-syntax">i</span><span class="plain-syntax"><64 : </span><span class="identifier-syntax">i</span><span class="plain-syntax">++) </span><span class="identifier-syntax">oops_workspace</span><span class="plain-syntax">-></span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">a_buffer</span><span class="plain-syntax">-></span><span class="identifier-syntax">i</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="comment-syntax">In case of an array entry corruption that shouldn't happen, but would be</span>
<span class="plain-syntax"> </span><span class="comment-syntax">disastrous if it did:</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifdef</span><span class="plain-syntax"> </span><span class="identifier-syntax">TARGET_ZCODE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">a_buffer</span><span class="plain-syntax">->0 = </span><span class="identifier-syntax">INPUT_BUFFER_LEN</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">a_table</span><span class="plain-syntax">->0 = </span><span class="constant-syntax">15</span><span class="plain-syntax">; </span><span class="comment-syntax">Allow to split input into this many words</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Endif</span><span class="plain-syntax">; </span><span class="comment-syntax">TARGET_</span>
<span class="plain-syntax"> </span><span class="comment-syntax">Print the prompt, and read in the words and dictionary addresses</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">PrintPrompt</span><span class="plain-syntax">();</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">DrawStatusLine</span><span class="plain-syntax">();</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">KeyboardPrimitive</span><span class="plain-syntax">(</span><span class="identifier-syntax">a_buffer</span><span class="plain-syntax">, </span><span class="identifier-syntax">a_table</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="comment-syntax">Set nw to the number of words</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifdef</span><span class="plain-syntax"> </span><span class="identifier-syntax">TARGET_ZCODE</span><span class="plain-syntax">; </span><span class="identifier-syntax">nw</span><span class="plain-syntax"> = </span><span class="identifier-syntax">a_table</span><span class="plain-syntax">->1; #</span><span class="identifier-syntax">Ifnot</span><span class="plain-syntax">; </span><span class="identifier-syntax">nw</span><span class="plain-syntax"> = </span><span class="identifier-syntax">a_table</span><span class="plain-syntax">-->0; #</span><span class="identifier-syntax">Endif</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="comment-syntax">If the line was blank, get a fresh line</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">nw</span><span class="plain-syntax"> == </span><span class="constant-syntax">0</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> @</span><span class="identifier-syntax">push</span><span class="plain-syntax"> </span><span class="identifier-syntax">etype</span><span class="plain-syntax">; </span><span class="identifier-syntax">etype</span><span class="plain-syntax"> = </span><span class="identifier-syntax">BLANKLINE_PE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">players_command</span><span class="plain-syntax"> = </span><span class="constant-syntax">100</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">BeginActivity</span><span class="plain-syntax">(</span><span class="identifier-syntax">PRINTING_A_PARSER_ERROR_ACT</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">ForActivity</span><span class="plain-syntax">(</span><span class="identifier-syntax">PRINTING_A_PARSER_ERROR_ACT</span><span class="plain-syntax">) == </span><span class="reserved-syntax">false</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">PARSER_ERROR_INTERNAL_RM</span><span class="plain-syntax">(</span><span class="character-syntax">'X'</span><span class="plain-syntax">, </span><span class="identifier-syntax">noun</span><span class="plain-syntax">); </span><span class="reserved-syntax">new_line</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">EndActivity</span><span class="plain-syntax">(</span><span class="identifier-syntax">PRINTING_A_PARSER_ERROR_ACT</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> @</span><span class="identifier-syntax">pull</span><span class="plain-syntax"> </span><span class="identifier-syntax">etype</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">continue</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="comment-syntax">Unless the opening word was OOPS, return</span>
<span class="plain-syntax"> </span><span class="comment-syntax">Conveniently, a_table-->1 is the first word on both the Z-machine and Glulx</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">w</span><span class="plain-syntax"> = </span><span class="identifier-syntax">a_table</span><span class="plain-syntax">-->1;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">w</span><span class="plain-syntax"> == </span><span class="identifier-syntax">OOPS1__WD</span><span class="plain-syntax"> </span><span class="reserved-syntax">or</span><span class="plain-syntax"> </span><span class="identifier-syntax">OOPS2__WD</span><span class="plain-syntax"> </span><span class="reserved-syntax">or</span><span class="plain-syntax"> </span><span class="identifier-syntax">OOPS3__WD</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">oops_from</span><span class="plain-syntax"> == </span><span class="constant-syntax">0</span><span class="plain-syntax">) { </span><span class="identifier-syntax">PARSER_COMMAND_INTERNAL_RM</span><span class="plain-syntax">(</span><span class="character-syntax">'A'</span><span class="plain-syntax">); </span><span class="reserved-syntax">new_line</span><span class="plain-syntax">; </span><span class="reserved-syntax">continue</span><span class="plain-syntax">; }</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">nw</span><span class="plain-syntax"> == </span><span class="constant-syntax">1</span><span class="plain-syntax">) { </span><span class="identifier-syntax">PARSER_COMMAND_INTERNAL_RM</span><span class="plain-syntax">(</span><span class="character-syntax">'B'</span><span class="plain-syntax">); </span><span class="reserved-syntax">new_line</span><span class="plain-syntax">; </span><span class="reserved-syntax">continue</span><span class="plain-syntax">; }</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">nw</span><span class="plain-syntax"> > </span><span class="constant-syntax">2</span><span class="plain-syntax">) { </span><span class="identifier-syntax">PARSER_COMMAND_INTERNAL_RM</span><span class="plain-syntax">(</span><span class="character-syntax">'C'</span><span class="plain-syntax">); </span><span class="reserved-syntax">new_line</span><span class="plain-syntax">; </span><span class="reserved-syntax">continue</span><span class="plain-syntax">; }</span>
<span class="plain-syntax"> </span><span class="comment-syntax">So now we know: there was a previous mistake, and the player has</span>
<span class="plain-syntax"> </span><span class="comment-syntax">attempted to correct a single word of it.</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">for</span><span class="plain-syntax"> (</span><span class="identifier-syntax">i</span><span class="plain-syntax">=0 : </span><span class="identifier-syntax">i</span><span class="plain-syntax"><</span><span class="identifier-syntax">INPUT_BUFFER_LEN</span><span class="plain-syntax"> : </span><span class="identifier-syntax">i</span><span class="plain-syntax">++) </span><span class="identifier-syntax">buffer2</span><span class="plain-syntax">-></span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">a_buffer</span><span class="plain-syntax">-></span><span class="identifier-syntax">i</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifdef</span><span class="plain-syntax"> </span><span class="identifier-syntax">TARGET_ZCODE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">x1</span><span class="plain-syntax"> = </span><span class="identifier-syntax">a_table</span><span class="plain-syntax">->9; </span><span class="comment-syntax">Start of word following "oops"</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">x2</span><span class="plain-syntax"> = </span><span class="identifier-syntax">a_table</span><span class="plain-syntax">->8; </span><span class="comment-syntax">Length of word following "oops"</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifnot</span><span class="plain-syntax">; </span><span class="comment-syntax">TARGET_GLULX</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">x1</span><span class="plain-syntax"> = </span><span class="identifier-syntax">a_table</span><span class="plain-syntax">-->6; </span><span class="comment-syntax">Start of word following "oops"</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">x2</span><span class="plain-syntax"> = </span><span class="identifier-syntax">a_table</span><span class="plain-syntax">-->5; </span><span class="comment-syntax">Length of word following "oops"</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Endif</span><span class="plain-syntax">; </span><span class="comment-syntax">TARGET_</span>
<span class="plain-syntax"> </span><span class="comment-syntax">Repair the buffer to the text that was in it before the "oops"</span>
<span class="plain-syntax"> </span><span class="comment-syntax">was typed:</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">for</span><span class="plain-syntax"> (</span><span class="identifier-syntax">i</span><span class="plain-syntax">=0 : </span><span class="identifier-syntax">i</span><span class="plain-syntax"><64 : </span><span class="identifier-syntax">i</span><span class="plain-syntax">++) </span><span class="identifier-syntax">a_buffer</span><span class="plain-syntax">-></span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">oops_workspace</span><span class="plain-syntax">-></span><span class="identifier-syntax">i</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">VM_Tokenise</span><span class="plain-syntax">(</span><span class="identifier-syntax">a_buffer</span><span class="plain-syntax">,</span><span class="identifier-syntax">a_table</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="comment-syntax">Work out the position in the buffer of the word to be corrected:</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifdef</span><span class="plain-syntax"> </span><span class="identifier-syntax">TARGET_ZCODE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">w</span><span class="plain-syntax"> = </span><span class="identifier-syntax">a_table</span><span class="plain-syntax">->(4*</span><span class="identifier-syntax">oops_from</span><span class="plain-syntax"> + </span><span class="constant-syntax">1</span><span class="plain-syntax">); </span><span class="comment-syntax">Start of word to go</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">w2</span><span class="plain-syntax"> = </span><span class="identifier-syntax">a_table</span><span class="plain-syntax">->(4*</span><span class="identifier-syntax">oops_from</span><span class="plain-syntax">); </span><span class="comment-syntax">Length of word to go</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifnot</span><span class="plain-syntax">; </span><span class="comment-syntax">TARGET_GLULX</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">w</span><span class="plain-syntax"> = </span><span class="identifier-syntax">a_table</span><span class="plain-syntax">-->(3*</span><span class="identifier-syntax">oops_from</span><span class="plain-syntax">); </span><span class="comment-syntax">Start of word to go</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">w2</span><span class="plain-syntax"> = </span><span class="identifier-syntax">a_table</span><span class="plain-syntax">-->(3*</span><span class="identifier-syntax">oops_from</span><span class="plain-syntax"> - </span><span class="constant-syntax">1</span><span class="plain-syntax">); </span><span class="comment-syntax">Length of word to go</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Endif</span><span class="plain-syntax">; </span><span class="comment-syntax">TARGET_</span>
<span class="plain-syntax"> </span><span class="comment-syntax">Write spaces over the word to be corrected:</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">for</span><span class="plain-syntax"> (</span><span class="identifier-syntax">i</span><span class="plain-syntax">=0 : </span><span class="identifier-syntax">i</span><span class="plain-syntax"><</span><span class="identifier-syntax">w2</span><span class="plain-syntax"> : </span><span class="identifier-syntax">i</span><span class="plain-syntax">++) </span><span class="identifier-syntax">a_buffer</span><span class="plain-syntax">->(</span><span class="identifier-syntax">i</span><span class="plain-syntax">+</span><span class="identifier-syntax">w</span><span class="plain-syntax">) = </span><span class="character-syntax">' '</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">w2</span><span class="plain-syntax"> < </span><span class="identifier-syntax">x2</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="comment-syntax">If the replacement is longer than the original, move up...</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">for</span><span class="plain-syntax"> (</span><span class="identifier-syntax">i</span><span class="plain-syntax">=</span><span class="identifier-syntax">INPUT_BUFFER_LEN</span><span class="plain-syntax">-1 : </span><span class="identifier-syntax">i</span><span class="plain-syntax">>=</span><span class="identifier-syntax">w</span><span class="plain-syntax">+</span><span class="identifier-syntax">x2</span><span class="plain-syntax"> : </span><span class="identifier-syntax">i</span><span class="plain-syntax">--)</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">a_buffer</span><span class="plain-syntax">-></span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">a_buffer</span><span class="plain-syntax">->(</span><span class="identifier-syntax">i</span><span class="plain-syntax">-</span><span class="identifier-syntax">x2</span><span class="plain-syntax">+</span><span class="identifier-syntax">w2</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="comment-syntax">...increasing buffer size accordingly.</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifdef</span><span class="plain-syntax"> </span><span class="identifier-syntax">TARGET_ZCODE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">a_buffer</span><span class="plain-syntax">->1 = (</span><span class="identifier-syntax">a_buffer</span><span class="plain-syntax">->1) + (</span><span class="identifier-syntax">x2</span><span class="plain-syntax">-</span><span class="identifier-syntax">w2</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifnot</span><span class="plain-syntax">; </span><span class="comment-syntax">TARGET_GLULX</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">a_buffer</span><span class="plain-syntax">-->0 = (</span><span class="identifier-syntax">a_buffer</span><span class="plain-syntax">-->0) + (</span><span class="identifier-syntax">x2</span><span class="plain-syntax">-</span><span class="identifier-syntax">w2</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Endif</span><span class="plain-syntax">; </span><span class="comment-syntax">TARGET_</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="comment-syntax">Write the correction in:</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">for</span><span class="plain-syntax"> (</span><span class="identifier-syntax">i</span><span class="plain-syntax">=0 : </span><span class="identifier-syntax">i</span><span class="plain-syntax"><</span><span class="identifier-syntax">x2</span><span class="plain-syntax"> : </span><span class="identifier-syntax">i</span><span class="plain-syntax">++) </span><span class="identifier-syntax">a_buffer</span><span class="plain-syntax">->(</span><span class="identifier-syntax">i</span><span class="plain-syntax">+</span><span class="identifier-syntax">w</span><span class="plain-syntax">) = </span><span class="identifier-syntax">buffer2</span><span class="plain-syntax">->(</span><span class="identifier-syntax">i</span><span class="plain-syntax">+</span><span class="identifier-syntax">x1</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">VM_Tokenise</span><span class="plain-syntax">(</span><span class="identifier-syntax">a_buffer</span><span class="plain-syntax">, </span><span class="identifier-syntax">a_table</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifdef</span><span class="plain-syntax"> </span><span class="identifier-syntax">TARGET_ZCODE</span><span class="plain-syntax">; </span><span class="identifier-syntax">nw</span><span class="plain-syntax"> = </span><span class="identifier-syntax">a_table</span><span class="plain-syntax">->1; #</span><span class="identifier-syntax">Ifnot</span><span class="plain-syntax">; </span><span class="identifier-syntax">nw</span><span class="plain-syntax"> = </span><span class="identifier-syntax">a_table</span><span class="plain-syntax">-->0; #</span><span class="identifier-syntax">Endif</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">nw</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="comment-syntax">Undo handling</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> ((</span><span class="identifier-syntax">w</span><span class="plain-syntax"> == </span><span class="identifier-syntax">UNDO1__WD</span><span class="plain-syntax"> </span><span class="reserved-syntax">or</span><span class="plain-syntax"> </span><span class="identifier-syntax">UNDO2__WD</span><span class="plain-syntax"> </span><span class="reserved-syntax">or</span><span class="plain-syntax"> </span><span class="identifier-syntax">UNDO3__WD</span><span class="plain-syntax">) && (</span><span class="identifier-syntax">nw</span><span class="plain-syntax">==1)) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Perform_Undo</span><span class="plain-syntax">();</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">continue</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">VM_Save_Undo</span><span class="plain-syntax">();</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">KIT_CONFIGURATION_BITMAP</span><span class="plain-syntax"> & </span><span class="identifier-syntax">PREVENT_UNDO_TCBIT</span><span class="plain-syntax">) </span><span class="identifier-syntax">undo_flag</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">else</span><span class="plain-syntax"> </span><span class="identifier-syntax">undo_flag</span><span class="plain-syntax"> = </span><span class="constant-syntax">2</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">i</span><span class="plain-syntax"> == -1) </span><span class="identifier-syntax">undo_flag</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">i</span><span class="plain-syntax"> == </span><span class="constant-syntax">0</span><span class="plain-syntax">) </span><span class="identifier-syntax">undo_flag</span><span class="plain-syntax"> = </span><span class="constant-syntax">1</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">i</span><span class="plain-syntax"> == </span><span class="constant-syntax">2</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">DealWithUndo</span><span class="plain-syntax">();</span>
<span class="comment-syntax"> VM_RestoreWindowColours();</span>
<span class="comment-syntax"> VM_Style(SUBHEADER_VMSTY);</span>
<span class="comment-syntax"> SL_Location(); print "^";</span>
<span class="comment-syntax"> VM_Style(NORMAL_VMSTY);</span>
<span class="comment-syntax"> IMMEDIATELY_UNDO_RM('E'); new_line;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">continue</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">nw</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax">];</span>
<span class="plain-syntax">[ </span><span class="identifier-syntax">DealWithUndo</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">VM_RestoreWindowColours</span><span class="plain-syntax">();</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">VM_Style</span><span class="plain-syntax">(</span><span class="identifier-syntax">SUBHEADER_VMSTY</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">SL_Location</span><span class="plain-syntax">(); </span><span class="reserved-syntax">print</span><span class="plain-syntax"> </span><span class="string-syntax">"^"</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">VM_Style</span><span class="plain-syntax">(</span><span class="identifier-syntax">NORMAL_VMSTY</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">IMMEDIATELY_UNDO_RM</span><span class="plain-syntax">(</span><span class="character-syntax">'E'</span><span class="plain-syntax">); </span><span class="reserved-syntax">new_line</span><span class="plain-syntax">;</span>
<span class="plain-syntax">];</span>
</pre>
<p class="commentary firstcommentary"><a id="SP11" class="paragraph-anchor"></a><b>§11. Parser Proper. </b>The main parser routine is something of a leviathan, and it has traditionally
been divided into 11 lettered parts:
</p>
<ul class="items"><li>(A) Get the input, do OOPS and AGAIN
</li><li>(B) Is it a direction, and so an implicit GO? If so go to (K)
</li><li>(C) Is anyone being addressed?
</li><li>(D) Get the command verb: try all the syntax lines for that verb
</li><li>(E) Break down a syntax line into analysed tokens
</li><li>(F) Look ahead for advance warning for <span class="extract"><span class="extract-syntax">multiexcept</span></span>/<span class="extract"><span class="extract-syntax">multiinside</span></span>
</li><li>(G) Parse each token in turn (calling <span class="extract"><span class="extract-syntax">ParseToken</span></span> to do most of the work)
</li><li>(H) Cheaply parse otherwise unrecognised conversation and return
</li><li>(I) Print best possible error message
</li><li>(J) Retry the whole lot
</li><li>(K) Last thing: check for THEN and further instructions(s), return.
</li></ul>
<p class="commentary">This lettering has been preserved here, with the code under each letter
now being the body of "Parser Letter A", "Parser Letter B" and so on.
</p>
<p class="commentary">Note that there are three different places where a return can happen.
The routine returns only when a sensible request has been made; for a
fairly thorough description of its output, which is written into the
<span class="extract"><span class="extract-syntax">parser_results</span></span> array and also into several globals (see "OrderOfPlay.i6t").
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax">[ </span><span class="identifier-syntax">Parser__parse</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">syntax</span><span class="plain-syntax"> </span><span class="identifier-syntax">line</span><span class="plain-syntax"> </span><span class="identifier-syntax">num_lines</span><span class="plain-syntax"> </span><span class="identifier-syntax">line_address</span><span class="plain-syntax"> </span><span class="identifier-syntax">i</span><span class="plain-syntax"> </span><span class="identifier-syntax">j</span><span class="plain-syntax"> </span><span class="identifier-syntax">k</span><span class="plain-syntax"> </span><span class="identifier-syntax">token</span><span class="plain-syntax"> </span><span class="identifier-syntax">l</span><span class="plain-syntax"> </span><span class="identifier-syntax">m</span><span class="plain-syntax"> </span><span class="identifier-syntax">inferred_go</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">cobj_flag</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">parser_results</span><span class="plain-syntax">--></span><span class="identifier-syntax">ACTION_PRES</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">parser_results</span><span class="plain-syntax">--></span><span class="identifier-syntax">NO_INPS_PRES</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">parser_results</span><span class="plain-syntax">--></span><span class="identifier-syntax">INP1_PRES</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">parser_results</span><span class="plain-syntax">--></span><span class="identifier-syntax">INP2_PRES</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">meta</span><span class="plain-syntax"> = </span><span class="reserved-syntax">false</span><span class="plain-syntax">;</span>
</pre>
<p class="commentary firstcommentary"><a id="SP12" class="paragraph-anchor"></a><b>§12. Parser Letter A. </b>Get the input, do OOPS and AGAIN.
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">held_back_mode</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">held_back_mode</span><span class="plain-syntax"> = </span><span class="reserved-syntax">false</span><span class="plain-syntax">; </span><span class="identifier-syntax">wn</span><span class="plain-syntax"> = </span><span class="identifier-syntax">hb_wn</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">verb_wordnum</span><span class="plain-syntax"> > </span><span class="constant-syntax">0</span><span class="plain-syntax">) </span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">WordAddress</span><span class="plain-syntax">(</span><span class="identifier-syntax">verb_wordnum</span><span class="plain-syntax">); </span><span class="reserved-syntax">else</span><span class="plain-syntax"> </span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">WordAddress</span><span class="plain-syntax">(1);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">j</span><span class="plain-syntax"> = </span><span class="identifier-syntax">WordAddress</span><span class="plain-syntax">(</span><span class="identifier-syntax">wn</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">i</span><span class="plain-syntax"><=</span><span class="identifier-syntax">j</span><span class="plain-syntax">) </span><span class="reserved-syntax">for</span><span class="plain-syntax"> (: </span><span class="identifier-syntax">i</span><span class="plain-syntax"><</span><span class="identifier-syntax">j</span><span class="plain-syntax"> : </span><span class="identifier-syntax">i</span><span class="plain-syntax">++) </span><span class="identifier-syntax">i</span><span class="plain-syntax">->0 = </span><span class="character-syntax">' '</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">NextWord</span><span class="plain-syntax">();</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">i</span><span class="plain-syntax"> == </span><span class="identifier-syntax">AGAIN1__WD</span><span class="plain-syntax"> </span><span class="reserved-syntax">or</span><span class="plain-syntax"> </span><span class="identifier-syntax">AGAIN2__WD</span><span class="plain-syntax"> </span><span class="reserved-syntax">or</span><span class="plain-syntax"> </span><span class="identifier-syntax">AGAIN3__WD</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="comment-syntax">Delete the words "then again" from the again buffer,</span>
<span class="plain-syntax"> </span><span class="comment-syntax">in which we have just realised that it must occur:</span>
<span class="plain-syntax"> </span><span class="comment-syntax">prevents an infinite loop on "i. again"</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">WordAddress</span><span class="plain-syntax">(</span><span class="identifier-syntax">wn</span><span class="plain-syntax">-2)-</span><span class="identifier-syntax">buffer</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">wn</span><span class="plain-syntax"> > </span><span class="identifier-syntax">num_words</span><span class="plain-syntax">) </span><span class="identifier-syntax">j</span><span class="plain-syntax"> = </span><span class="identifier-syntax">INPUT_BUFFER_LEN</span><span class="plain-syntax">-1;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">else</span><span class="plain-syntax"> </span><span class="identifier-syntax">j</span><span class="plain-syntax"> = </span><span class="identifier-syntax">WordAddress</span><span class="plain-syntax">(</span><span class="identifier-syntax">wn</span><span class="plain-syntax">)-</span><span class="identifier-syntax">buffer</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">for</span><span class="plain-syntax"> (: </span><span class="identifier-syntax">i</span><span class="plain-syntax"><</span><span class="identifier-syntax">j</span><span class="plain-syntax"> : </span><span class="identifier-syntax">i</span><span class="plain-syntax">++) </span><span class="identifier-syntax">buffer3</span><span class="plain-syntax">-></span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="character-syntax">' '</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">VM_Tokenise</span><span class="plain-syntax">(</span><span class="identifier-syntax">buffer</span><span class="plain-syntax">, </span><span class="identifier-syntax">parse</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">jump</span><span class="plain-syntax"> </span><span class="identifier-syntax">ReParse</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> .</span><span class="identifier-syntax">ReType</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">cobj_flag</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">actors_location</span><span class="plain-syntax"> = </span><span class="identifier-syntax">ScopeCeiling</span><span class="plain-syntax">(</span><span class="identifier-syntax">player</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">BeginActivity</span><span class="plain-syntax">(</span><span class="identifier-syntax">READING_A_COMMAND_ACT</span><span class="plain-syntax">); </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">ForActivity</span><span class="plain-syntax">(</span><span class="identifier-syntax">READING_A_COMMAND_ACT</span><span class="plain-syntax">)==</span><span class="reserved-syntax">false</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Keyboard</span><span class="plain-syntax">(</span><span class="identifier-syntax">buffer</span><span class="plain-syntax">,</span><span class="identifier-syntax">parse</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">num_words</span><span class="plain-syntax"> = </span><span class="identifier-syntax">WordCount</span><span class="plain-syntax">(); </span><span class="identifier-syntax">players_command</span><span class="plain-syntax"> = </span><span class="constant-syntax">100</span><span class="plain-syntax"> + </span><span class="identifier-syntax">num_words</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> } </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">EndActivity</span><span class="plain-syntax">(</span><span class="identifier-syntax">READING_A_COMMAND_ACT</span><span class="plain-syntax">)) </span><span class="reserved-syntax">jump</span><span class="plain-syntax"> </span><span class="identifier-syntax">ReType</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> .</span><span class="identifier-syntax">ReParse</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">parser_inflection</span><span class="plain-syntax"> = </span><span class="identifier-syntax">name</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="comment-syntax">Initially assume the command is aimed at the player, and the verb</span>
<span class="plain-syntax"> </span><span class="comment-syntax">is the first word</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">num_words</span><span class="plain-syntax"> = </span><span class="identifier-syntax">WordCount</span><span class="plain-syntax">(); </span><span class="identifier-syntax">players_command</span><span class="plain-syntax"> = </span><span class="constant-syntax">100</span><span class="plain-syntax"> + </span><span class="identifier-syntax">num_words</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">wn</span><span class="plain-syntax"> = </span><span class="constant-syntax">1</span><span class="plain-syntax">; </span><span class="identifier-syntax">inferred_go</span><span class="plain-syntax"> = </span><span class="reserved-syntax">false</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">LanguageToInformese</span><span class="plain-syntax">();</span>
<span class="plain-syntax"> </span><span class="comment-syntax">Re-tokenise:</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">VM_Tokenise</span><span class="plain-syntax">(</span><span class="identifier-syntax">buffer</span><span class="plain-syntax">,</span><span class="identifier-syntax">parse</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">num_words</span><span class="plain-syntax"> = </span><span class="identifier-syntax">WordCount</span><span class="plain-syntax">(); </span><span class="identifier-syntax">players_command</span><span class="plain-syntax"> = </span><span class="constant-syntax">100</span><span class="plain-syntax"> + </span><span class="identifier-syntax">num_words</span><span class="plain-syntax">; </span><span class="identifier-syntax">token_filter</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">allow_plurals</span><span class="plain-syntax"> = </span><span class="reserved-syntax">true</span><span class="plain-syntax">; </span><span class="identifier-syntax">ResetDescriptors</span><span class="plain-syntax">();</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">k</span><span class="plain-syntax">=0;</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifdef</span><span class="plain-syntax"> </span><span class="identifier-syntax">DEBUG</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">parser_trace</span><span class="plain-syntax"> >= </span><span class="constant-syntax">2</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">print</span><span class="plain-syntax"> </span><span class="string-syntax">"[ "</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">for</span><span class="plain-syntax"> (</span><span class="identifier-syntax">i</span><span class="plain-syntax">=0 : </span><span class="identifier-syntax">i</span><span class="plain-syntax"><</span><span class="identifier-syntax">num_words</span><span class="plain-syntax"> : </span><span class="identifier-syntax">i</span><span class="plain-syntax">++) {</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifdef</span><span class="plain-syntax"> </span><span class="identifier-syntax">TARGET_ZCODE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">j</span><span class="plain-syntax"> = </span><span class="identifier-syntax">parse</span><span class="plain-syntax">-->(</span><span class="identifier-syntax">i</span><span class="plain-syntax">*2 + </span><span class="constant-syntax">1</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifnot</span><span class="plain-syntax">; </span><span class="comment-syntax">TARGET_GLULX</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">j</span><span class="plain-syntax"> = </span><span class="identifier-syntax">parse</span><span class="plain-syntax">-->(</span><span class="identifier-syntax">i</span><span class="plain-syntax">*3 + </span><span class="constant-syntax">1</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Endif</span><span class="plain-syntax">; </span><span class="comment-syntax">TARGET_</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">k</span><span class="plain-syntax"> = </span><span class="identifier-syntax">WordAddress</span><span class="plain-syntax">(</span><span class="identifier-syntax">i</span><span class="plain-syntax">+1);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">l</span><span class="plain-syntax"> = </span><span class="identifier-syntax">WordLength</span><span class="plain-syntax">(</span><span class="identifier-syntax">i</span><span class="plain-syntax">+1);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">print</span><span class="plain-syntax"> </span><span class="string-syntax">"~"</span><span class="plain-syntax">; </span><span class="reserved-syntax">for</span><span class="plain-syntax"> (</span><span class="identifier-syntax">m</span><span class="plain-syntax">=0 : </span><span class="identifier-syntax">m</span><span class="plain-syntax"><</span><span class="identifier-syntax">l</span><span class="plain-syntax"> : </span><span class="identifier-syntax">m</span><span class="plain-syntax">++) </span><span class="reserved-syntax">print</span><span class="plain-syntax"> (</span><span class="identifier-syntax">char</span><span class="plain-syntax">) </span><span class="identifier-syntax">k</span><span class="plain-syntax">-></span><span class="identifier-syntax">m</span><span class="plain-syntax">; </span><span class="reserved-syntax">print</span><span class="plain-syntax"> </span><span class="string-syntax">"~ "</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">j</span><span class="plain-syntax"> == </span><span class="constant-syntax">0</span><span class="plain-syntax">) </span><span class="reserved-syntax">print</span><span class="plain-syntax"> </span><span class="string-syntax">"?"</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">else</span><span class="plain-syntax"> {</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifdef</span><span class="plain-syntax"> </span><span class="identifier-syntax">TARGET_ZCODE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">UnsignedCompare</span><span class="plain-syntax">(</span><span class="identifier-syntax">j</span><span class="plain-syntax">, </span><span class="identifier-syntax">HDR_DICTIONARY</span><span class="plain-syntax">-->0) >= </span><span class="constant-syntax">0</span><span class="plain-syntax"> &&</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">UnsignedCompare</span><span class="plain-syntax">(</span><span class="identifier-syntax">j</span><span class="plain-syntax">, </span><span class="identifier-syntax">HDR_HIGHMEMORY</span><span class="plain-syntax">-->0) < </span><span class="constant-syntax">0</span><span class="plain-syntax">)</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">print</span><span class="plain-syntax"> (</span><span class="identifier-syntax">address</span><span class="plain-syntax">) </span><span class="identifier-syntax">j</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">else</span><span class="plain-syntax"> </span><span class="reserved-syntax">print</span><span class="plain-syntax"> </span><span class="identifier-syntax">j</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifnot</span><span class="plain-syntax">; </span><span class="comment-syntax">TARGET_GLULX</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">j</span><span class="plain-syntax">->0 == </span><span class="constant-syntax">$60</span><span class="plain-syntax">) </span><span class="reserved-syntax">print</span><span class="plain-syntax"> (</span><span class="identifier-syntax">address</span><span class="plain-syntax">) </span><span class="identifier-syntax">j</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">else</span><span class="plain-syntax"> </span><span class="reserved-syntax">print</span><span class="plain-syntax"> </span><span class="identifier-syntax">j</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Endif</span><span class="plain-syntax">; </span><span class="comment-syntax">TARGET_</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">i</span><span class="plain-syntax"> ~= </span><span class="identifier-syntax">num_words</span><span class="plain-syntax">-1) </span><span class="reserved-syntax">print</span><span class="plain-syntax"> </span><span class="string-syntax">" / "</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">print</span><span class="plain-syntax"> </span><span class="string-syntax">" ]^"</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Endif</span><span class="plain-syntax">; </span><span class="comment-syntax">DEBUG</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">verb_wordnum</span><span class="plain-syntax"> = </span><span class="constant-syntax">1</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">actor</span><span class="plain-syntax"> = </span><span class="identifier-syntax">player</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">actors_location</span><span class="plain-syntax"> = </span><span class="identifier-syntax">ScopeCeiling</span><span class="plain-syntax">(</span><span class="identifier-syntax">player</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">usual_grammar_after</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> .</span><span class="identifier-syntax">AlmostReParse</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">scope_token</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">action_to_be</span><span class="plain-syntax"> = </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="comment-syntax">Begin from what we currently think is the verb word</span>
<span class="plain-syntax"> .</span><span class="identifier-syntax">BeginCommand</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">wn</span><span class="plain-syntax"> = </span><span class="identifier-syntax">verb_wordnum</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">verb_word</span><span class="plain-syntax"> = </span><span class="identifier-syntax">NextWordStopped</span><span class="plain-syntax">();</span>
<span class="plain-syntax"> </span><span class="comment-syntax">If there's no input here, we must have something like "person,".</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">verb_word</span><span class="plain-syntax"> == -1) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">best_etype</span><span class="plain-syntax"> = </span><span class="identifier-syntax">STUCK_PE</span><span class="plain-syntax">; </span><span class="reserved-syntax">jump</span><span class="plain-syntax"> </span><span class="identifier-syntax">GiveError</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">verb_word</span><span class="plain-syntax"> == </span><span class="identifier-syntax">comma_word</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">best_etype</span><span class="plain-syntax"> = </span><span class="identifier-syntax">COMMABEGIN_PE</span><span class="plain-syntax">; </span><span class="reserved-syntax">jump</span><span class="plain-syntax"> </span><span class="identifier-syntax">GiveError</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="comment-syntax">Now try for "again" or "g", which are special cases: don't allow "again" if nothing</span>
<span class="plain-syntax"> </span><span class="comment-syntax">has previously been typed; simply copy the previous text across</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">verb_word</span><span class="plain-syntax"> == </span><span class="identifier-syntax">AGAIN2__WD</span><span class="plain-syntax"> </span><span class="reserved-syntax">or</span><span class="plain-syntax"> </span><span class="identifier-syntax">AGAIN3__WD</span><span class="plain-syntax">) </span><span class="identifier-syntax">verb_word</span><span class="plain-syntax"> = </span><span class="identifier-syntax">AGAIN1__WD</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">verb_word</span><span class="plain-syntax"> == </span><span class="identifier-syntax">AGAIN1__WD</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">actor</span><span class="plain-syntax"> ~= </span><span class="identifier-syntax">player</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">best_etype</span><span class="plain-syntax"> = </span><span class="identifier-syntax">ANIMAAGAIN_PE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">jump</span><span class="plain-syntax"> </span><span class="identifier-syntax">GiveError</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifdef</span><span class="plain-syntax"> </span><span class="identifier-syntax">TARGET_ZCODE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">buffer3</span><span class="plain-syntax">->1 == </span><span class="constant-syntax">0</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">PARSER_COMMAND_INTERNAL_RM</span><span class="plain-syntax">(</span><span class="character-syntax">'D'</span><span class="plain-syntax">); </span><span class="reserved-syntax">new_line</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">jump</span><span class="plain-syntax"> </span><span class="identifier-syntax">ReType</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifnot</span><span class="plain-syntax">; </span><span class="comment-syntax">TARGET_GLULX</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">buffer3</span><span class="plain-syntax">-->0 == </span><span class="constant-syntax">0</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">PARSER_COMMAND_INTERNAL_RM</span><span class="plain-syntax">(</span><span class="character-syntax">'D'</span><span class="plain-syntax">); </span><span class="reserved-syntax">new_line</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">jump</span><span class="plain-syntax"> </span><span class="identifier-syntax">ReType</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Endif</span><span class="plain-syntax">; </span><span class="comment-syntax">TARGET_</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">for</span><span class="plain-syntax"> (</span><span class="identifier-syntax">i</span><span class="plain-syntax">=0 : </span><span class="identifier-syntax">i</span><span class="plain-syntax"><</span><span class="identifier-syntax">INPUT_BUFFER_LEN</span><span class="plain-syntax"> : </span><span class="identifier-syntax">i</span><span class="plain-syntax">++) </span><span class="identifier-syntax">buffer</span><span class="plain-syntax">-></span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">buffer3</span><span class="plain-syntax">-></span><span class="identifier-syntax">i</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">VM_Tokenise</span><span class="plain-syntax">(</span><span class="identifier-syntax">buffer</span><span class="plain-syntax">,</span><span class="identifier-syntax">parse</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">num_words</span><span class="plain-syntax"> = </span><span class="identifier-syntax">WordCount</span><span class="plain-syntax">(); </span><span class="identifier-syntax">players_command</span><span class="plain-syntax"> = </span><span class="constant-syntax">100</span><span class="plain-syntax"> + </span><span class="identifier-syntax">num_words</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">jump</span><span class="plain-syntax"> </span><span class="identifier-syntax">ReParse</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="comment-syntax">Save the present input in case of an "again" next time</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">verb_word</span><span class="plain-syntax"> ~= </span><span class="identifier-syntax">AGAIN1__WD</span><span class="plain-syntax">)</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">for</span><span class="plain-syntax"> (</span><span class="identifier-syntax">i</span><span class="plain-syntax">=0 : </span><span class="identifier-syntax">i</span><span class="plain-syntax"><</span><span class="identifier-syntax">INPUT_BUFFER_LEN</span><span class="plain-syntax"> : </span><span class="identifier-syntax">i</span><span class="plain-syntax">++) </span><span class="identifier-syntax">buffer3</span><span class="plain-syntax">-></span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">buffer</span><span class="plain-syntax">-></span><span class="identifier-syntax">i</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">usual_grammar_after</span><span class="plain-syntax"> == </span><span class="constant-syntax">0</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">j</span><span class="plain-syntax"> = </span><span class="identifier-syntax">verb_wordnum</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">RunRoutines</span><span class="plain-syntax">(</span><span class="identifier-syntax">actor</span><span class="plain-syntax">, </span><span class="identifier-syntax">grammar</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifdef</span><span class="plain-syntax"> </span><span class="identifier-syntax">DEBUG</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">parser_trace</span><span class="plain-syntax"> >= </span><span class="constant-syntax">2</span><span class="plain-syntax"> && </span><span class="identifier-syntax">actor</span><span class="plain-syntax">.</span><span class="identifier-syntax">grammar</span><span class="plain-syntax"> ~= </span><span class="constant-syntax">0</span><span class="plain-syntax"> </span><span class="reserved-syntax">or</span><span class="plain-syntax"> </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">)</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">print</span><span class="plain-syntax"> </span><span class="string-syntax">" [Grammar property returned "</span><span class="plain-syntax">, </span><span class="identifier-syntax">i</span><span class="plain-syntax">, </span><span class="string-syntax">"]^"</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Endif</span><span class="plain-syntax">; </span><span class="comment-syntax">DEBUG</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> ((</span><span class="identifier-syntax">i</span><span class="plain-syntax"> ~= </span><span class="constant-syntax">0</span><span class="plain-syntax"> </span><span class="reserved-syntax">or</span><span class="plain-syntax"> </span><span class="constant-syntax">1</span><span class="plain-syntax">) && (</span><span class="identifier-syntax">VM_InvalidDictionaryAddress</span><span class="plain-syntax">(</span><span class="identifier-syntax">i</span><span class="plain-syntax">))) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">usual_grammar_after</span><span class="plain-syntax"> = </span><span class="identifier-syntax">verb_wordnum</span><span class="plain-syntax">; </span><span class="identifier-syntax">i</span><span class="plain-syntax">=-</span><span class="identifier-syntax">i</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">i</span><span class="plain-syntax"> == </span><span class="constant-syntax">1</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">parser_results</span><span class="plain-syntax">--></span><span class="identifier-syntax">ACTION_PRES</span><span class="plain-syntax"> = </span><span class="identifier-syntax">action</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">parser_results</span><span class="plain-syntax">--></span><span class="identifier-syntax">NO_INPS_PRES</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">parser_results</span><span class="plain-syntax">--></span><span class="identifier-syntax">INP1_PRES</span><span class="plain-syntax"> = </span><span class="identifier-syntax">noun</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">parser_results</span><span class="plain-syntax">--></span><span class="identifier-syntax">INP2_PRES</span><span class="plain-syntax"> = </span><span class="identifier-syntax">second</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">noun</span><span class="plain-syntax">) </span><span class="identifier-syntax">parser_results</span><span class="plain-syntax">--></span><span class="identifier-syntax">NO_INPS_PRES</span><span class="plain-syntax"> = </span><span class="constant-syntax">1</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">second</span><span class="plain-syntax">) </span><span class="identifier-syntax">parser_results</span><span class="plain-syntax">--></span><span class="identifier-syntax">NO_INPS_PRES</span><span class="plain-syntax"> = </span><span class="constant-syntax">2</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">rtrue</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">i</span><span class="plain-syntax"> ~= </span><span class="constant-syntax">0</span><span class="plain-syntax">) { </span><span class="identifier-syntax">verb_word</span><span class="plain-syntax"> = </span><span class="identifier-syntax">i</span><span class="plain-syntax">; </span><span class="identifier-syntax">wn</span><span class="plain-syntax">--; </span><span class="identifier-syntax">verb_wordnum</span><span class="plain-syntax">--; }</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">else</span><span class="plain-syntax"> { </span><span class="identifier-syntax">wn</span><span class="plain-syntax"> = </span><span class="identifier-syntax">verb_wordnum</span><span class="plain-syntax">; </span><span class="identifier-syntax">verb_word</span><span class="plain-syntax"> = </span><span class="identifier-syntax">NextWord</span><span class="plain-syntax">(); }</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">else</span><span class="plain-syntax"> </span><span class="identifier-syntax">usual_grammar_after</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
</pre>
<p class="commentary firstcommentary"><a id="SP13" class="paragraph-anchor"></a><b>§13. Parser Letter B. </b>Is the command a direction name, and so an implicit GO? If so, go to (K).
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">verb_word</span><span class="plain-syntax"> == </span><span class="constant-syntax">0</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">wn</span><span class="plain-syntax">; </span><span class="identifier-syntax">verb_word</span><span class="plain-syntax"> = </span><span class="identifier-syntax">LanguageIsVerb</span><span class="plain-syntax">(</span><span class="identifier-syntax">buffer</span><span class="plain-syntax">, </span><span class="identifier-syntax">parse</span><span class="plain-syntax">, </span><span class="identifier-syntax">verb_wordnum</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">wn</span><span class="plain-syntax"> = </span><span class="identifier-syntax">i</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="comment-syntax">If the first word is not listed as a verb, it must be a direction</span>
<span class="plain-syntax"> </span><span class="comment-syntax">or the name of someone to talk to</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">verb_word</span><span class="plain-syntax"> == </span><span class="constant-syntax">0</span><span class="plain-syntax"> || ((</span><span class="identifier-syntax">verb_word</span><span class="plain-syntax">->#</span><span class="identifier-syntax">dict_par1</span><span class="plain-syntax">) & </span><span class="constant-syntax">1</span><span class="plain-syntax">) == </span><span class="constant-syntax">0</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="comment-syntax">So is the first word an object contained in the special object "compass"</span>
<span class="plain-syntax"> </span><span class="comment-syntax">(i.e., a direction)? This needs use of NounDomain, a routine which</span>
<span class="plain-syntax"> </span><span class="comment-syntax">does the object matching, returning the object number, or 0 if none found,</span>
<span class="plain-syntax"> </span><span class="comment-syntax">or REPARSE_CODE if it has restructured the parse table so the whole parse</span>
<span class="plain-syntax"> </span><span class="comment-syntax">must be begun again...</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">wn</span><span class="plain-syntax"> = </span><span class="identifier-syntax">verb_wordnum</span><span class="plain-syntax">; </span><span class="identifier-syntax">indef_mode</span><span class="plain-syntax"> = </span><span class="reserved-syntax">false</span><span class="plain-syntax">; </span><span class="identifier-syntax">token_filter</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">; </span><span class="identifier-syntax">parameters</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> @</span><span class="identifier-syntax">push</span><span class="plain-syntax"> </span><span class="identifier-syntax">actor</span><span class="plain-syntax">; @</span><span class="identifier-syntax">push</span><span class="plain-syntax"> </span><span class="identifier-syntax">action</span><span class="plain-syntax">; @</span><span class="identifier-syntax">push</span><span class="plain-syntax"> </span><span class="identifier-syntax">action_to_be</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">actor</span><span class="plain-syntax"> = </span><span class="identifier-syntax">player</span><span class="plain-syntax">; </span><span class="identifier-syntax">meta</span><span class="plain-syntax"> = </span><span class="reserved-syntax">false</span><span class="plain-syntax">; </span><span class="identifier-syntax">action</span><span class="plain-syntax"> = ##</span><span class="identifier-syntax">Go</span><span class="plain-syntax">; </span><span class="identifier-syntax">action_to_be</span><span class="plain-syntax"> = ##</span><span class="identifier-syntax">Go</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">l</span><span class="plain-syntax"> = </span><span class="identifier-syntax">NounDomain</span><span class="plain-syntax">(</span><span class="identifier-syntax">Compass</span><span class="plain-syntax">, </span><span class="constant-syntax">0</span><span class="plain-syntax">, </span><span class="constant-syntax">0</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> @</span><span class="identifier-syntax">pull</span><span class="plain-syntax"> </span><span class="identifier-syntax">action_to_be</span><span class="plain-syntax">; @</span><span class="identifier-syntax">pull</span><span class="plain-syntax"> </span><span class="identifier-syntax">action</span><span class="plain-syntax">; @</span><span class="identifier-syntax">pull</span><span class="plain-syntax"> </span><span class="identifier-syntax">actor</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">l</span><span class="plain-syntax"> == </span><span class="identifier-syntax">REPARSE_CODE</span><span class="plain-syntax">) </span><span class="reserved-syntax">jump</span><span class="plain-syntax"> </span><span class="identifier-syntax">ReParse</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="comment-syntax">If it is a direction, send back the results:</span>
<span class="plain-syntax"> </span><span class="comment-syntax">action=GoSub, no of arguments=1, argument 1=the direction.</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> ((</span><span class="identifier-syntax">l</span><span class="plain-syntax">~=0) && (</span><span class="identifier-syntax">l</span><span class="plain-syntax"> </span><span class="reserved-syntax">ofclass</span><span class="plain-syntax"> </span><span class="identifier-syntax">K3_direction</span><span class="plain-syntax">)) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">parser_results</span><span class="plain-syntax">--></span><span class="identifier-syntax">ACTION_PRES</span><span class="plain-syntax"> = ##</span><span class="identifier-syntax">Go</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">parser_results</span><span class="plain-syntax">--></span><span class="identifier-syntax">NO_INPS_PRES</span><span class="plain-syntax"> = </span><span class="constant-syntax">1</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">parser_results</span><span class="plain-syntax">--></span><span class="identifier-syntax">INP1_PRES</span><span class="plain-syntax"> = </span><span class="identifier-syntax">l</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">inferred_go</span><span class="plain-syntax"> = </span><span class="reserved-syntax">true</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">jump</span><span class="plain-syntax"> </span><span class="identifier-syntax">LookForMore</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> } </span><span class="comment-syntax">end of first-word-not-a-verb</span>
</pre>
<p class="commentary firstcommentary"><a id="SP14" class="paragraph-anchor"></a><b>§14. Parser Letter C. </b>Is anyone being addressed?
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax"> </span><span class="comment-syntax">Only check for a comma (a "someone, do something" command) if we are</span>
<span class="plain-syntax"> </span><span class="comment-syntax">not already in the middle of one. (This simplification stops us from</span>
<span class="plain-syntax"> </span><span class="comment-syntax">worrying about "robot, wizard, you are an idiot", telling the robot to</span>
<span class="plain-syntax"> </span><span class="comment-syntax">tell the wizard that she is an idiot.)</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">actor</span><span class="plain-syntax"> == </span><span class="identifier-syntax">player</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">for</span><span class="plain-syntax"> (</span><span class="identifier-syntax">j</span><span class="plain-syntax">=2 : </span><span class="identifier-syntax">j</span><span class="plain-syntax"><=</span><span class="identifier-syntax">num_words</span><span class="plain-syntax"> : </span><span class="identifier-syntax">j</span><span class="plain-syntax">++) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">i</span><span class="plain-syntax">=</span><span class="identifier-syntax">NextWord</span><span class="plain-syntax">();</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">i</span><span class="plain-syntax"> == </span><span class="identifier-syntax">comma_word</span><span class="plain-syntax">) </span><span class="reserved-syntax">jump</span><span class="plain-syntax"> </span><span class="identifier-syntax">Conversation</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">jump</span><span class="plain-syntax"> </span><span class="identifier-syntax">NotConversation</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="comment-syntax">NextWord nudges the word number wn on by one each time, so we've now</span>
<span class="plain-syntax"> </span><span class="comment-syntax">advanced past a comma. (A comma is a word all on its own in the table.)</span>
<span class="plain-syntax"> .</span><span class="identifier-syntax">Conversation</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">j</span><span class="plain-syntax"> = </span><span class="identifier-syntax">wn</span><span class="plain-syntax"> - </span><span class="constant-syntax">1</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="comment-syntax">Use NounDomain (in the context of "animate creature") to see if the</span>
<span class="plain-syntax"> </span><span class="comment-syntax">words make sense as the name of someone held or nearby</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">wn</span><span class="plain-syntax"> = </span><span class="constant-syntax">1</span><span class="plain-syntax">; </span><span class="identifier-syntax">lookahead</span><span class="plain-syntax"> = </span><span class="identifier-syntax">HELD_TOKEN</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">scope_reason</span><span class="plain-syntax"> = </span><span class="identifier-syntax">TALKING_REASON</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">l</span><span class="plain-syntax"> = </span><span class="identifier-syntax">NounDomain</span><span class="plain-syntax">(</span><span class="identifier-syntax">player</span><span class="plain-syntax">, </span><span class="identifier-syntax">actors_location</span><span class="plain-syntax">, </span><span class="identifier-syntax">CREATURE_TOKEN</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">scope_reason</span><span class="plain-syntax"> = </span><span class="identifier-syntax">PARSING_REASON</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">l</span><span class="plain-syntax"> == </span><span class="identifier-syntax">REPARSE_CODE</span><span class="plain-syntax">) </span><span class="reserved-syntax">jump</span><span class="plain-syntax"> </span><span class="identifier-syntax">ReParse</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">l</span><span class="plain-syntax"> == </span><span class="constant-syntax">0</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">verb_word</span><span class="plain-syntax"> && ((</span><span class="identifier-syntax">verb_word</span><span class="plain-syntax">->#</span><span class="identifier-syntax">dict_par1</span><span class="plain-syntax">) & </span><span class="constant-syntax">1</span><span class="plain-syntax">)) </span><span class="reserved-syntax">jump</span><span class="plain-syntax"> </span><span class="identifier-syntax">NotConversation</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">best_etype</span><span class="plain-syntax"> = </span><span class="identifier-syntax">MISSINGPERSON_PE</span><span class="plain-syntax">; </span><span class="reserved-syntax">jump</span><span class="plain-syntax"> </span><span class="identifier-syntax">GiveError</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> .</span><span class="identifier-syntax">Conversation2</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="comment-syntax">The object addressed must at least be "talkable" if not actually "animate"</span>
<span class="plain-syntax"> </span><span class="comment-syntax">(the distinction allows, for instance, a microphone to be spoken to,</span>
<span class="plain-syntax"> </span><span class="comment-syntax">without the parser thinking that the microphone is human).</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">l</span><span class="plain-syntax"> </span><span class="reserved-syntax">hasnt</span><span class="plain-syntax"> </span><span class="identifier-syntax">animate</span><span class="plain-syntax"> && </span><span class="identifier-syntax">l</span><span class="plain-syntax"> </span><span class="reserved-syntax">hasnt</span><span class="plain-syntax"> </span><span class="identifier-syntax">talkable</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">best_etype</span><span class="plain-syntax"> = </span><span class="identifier-syntax">ANIMALISTEN_PE</span><span class="plain-syntax">; </span><span class="identifier-syntax">noun</span><span class="plain-syntax"> = </span><span class="identifier-syntax">l</span><span class="plain-syntax">; </span><span class="reserved-syntax">jump</span><span class="plain-syntax"> </span><span class="identifier-syntax">GiveError</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="comment-syntax">Check that there aren't any mystery words between the end of the person's</span>
<span class="plain-syntax"> </span><span class="comment-syntax">name and the comma (eg, throw out "dwarf sdfgsdgs, go north").</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">wn</span><span class="plain-syntax"> ~= </span><span class="identifier-syntax">j</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">verb_word</span><span class="plain-syntax"> && ((</span><span class="identifier-syntax">verb_word</span><span class="plain-syntax">->#</span><span class="identifier-syntax">dict_par1</span><span class="plain-syntax">) & </span><span class="constant-syntax">1</span><span class="plain-syntax">)) </span><span class="reserved-syntax">jump</span><span class="plain-syntax"> </span><span class="identifier-syntax">NotConversation</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">best_etype</span><span class="plain-syntax"> = </span><span class="identifier-syntax">TOTALK_PE</span><span class="plain-syntax">; </span><span class="reserved-syntax">jump</span><span class="plain-syntax"> </span><span class="identifier-syntax">GiveError</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="comment-syntax">The player has now successfully named someone. Adjust "him", "her", "it":</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">PronounNotice</span><span class="plain-syntax">(</span><span class="identifier-syntax">l</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="comment-syntax">Set the global variable "actor", adjust the number of the first word,</span>
<span class="plain-syntax"> </span><span class="comment-syntax">and begin parsing again from there.</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">verb_wordnum</span><span class="plain-syntax"> = </span><span class="identifier-syntax">j</span><span class="plain-syntax"> + </span><span class="constant-syntax">1</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="comment-syntax">Stop things like "me, again":</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">l</span><span class="plain-syntax"> == </span><span class="identifier-syntax">player</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">wn</span><span class="plain-syntax"> = </span><span class="identifier-syntax">verb_wordnum</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">NextWordStopped</span><span class="plain-syntax">() == </span><span class="identifier-syntax">AGAIN1__WD</span><span class="plain-syntax"> </span><span class="reserved-syntax">or</span><span class="plain-syntax"> </span><span class="identifier-syntax">AGAIN2__WD</span><span class="plain-syntax"> </span><span class="reserved-syntax">or</span><span class="plain-syntax"> </span><span class="identifier-syntax">AGAIN3__WD</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">best_etype</span><span class="plain-syntax"> = </span><span class="identifier-syntax">ANIMAAGAIN_PE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">jump</span><span class="plain-syntax"> </span><span class="identifier-syntax">GiveError</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">actor</span><span class="plain-syntax"> = </span><span class="identifier-syntax">l</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">actors_location</span><span class="plain-syntax"> = </span><span class="identifier-syntax">ScopeCeiling</span><span class="plain-syntax">(</span><span class="identifier-syntax">l</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifdef</span><span class="plain-syntax"> </span><span class="identifier-syntax">DEBUG</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">parser_trace</span><span class="plain-syntax"> >= </span><span class="constant-syntax">1</span><span class="plain-syntax">)</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">print</span><span class="plain-syntax"> </span><span class="string-syntax">"[Actor is "</span><span class="plain-syntax">, (</span><span class="identifier-syntax">the</span><span class="plain-syntax">) </span><span class="identifier-syntax">actor</span><span class="plain-syntax">, </span><span class="string-syntax">" in "</span><span class="plain-syntax">, (</span><span class="identifier-syntax">name</span><span class="plain-syntax">) </span><span class="identifier-syntax">actors_location</span><span class="plain-syntax">, </span><span class="string-syntax">"]^"</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Endif</span><span class="plain-syntax">; </span><span class="comment-syntax">DEBUG</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">jump</span><span class="plain-syntax"> </span><span class="identifier-syntax">BeginCommand</span><span class="plain-syntax">;</span>
</pre>
<p class="commentary firstcommentary"><a id="SP15" class="paragraph-anchor"></a><b>§15. Parser Letter D. </b>Get the verb: try all the syntax lines for that verb.
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax"> .</span><span class="identifier-syntax">NotConversation</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">verb_word</span><span class="plain-syntax"> == </span><span class="constant-syntax">0</span><span class="plain-syntax"> || ((</span><span class="identifier-syntax">verb_word</span><span class="plain-syntax">->#</span><span class="identifier-syntax">dict_par1</span><span class="plain-syntax">) & </span><span class="constant-syntax">1</span><span class="plain-syntax">) == </span><span class="constant-syntax">0</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">verb_word</span><span class="plain-syntax"> = </span><span class="identifier-syntax">UnknownVerb</span><span class="plain-syntax">(</span><span class="identifier-syntax">verb_word</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">verb_word</span><span class="plain-syntax"> ~= </span><span class="constant-syntax">0</span><span class="plain-syntax">) </span><span class="reserved-syntax">jump</span><span class="plain-syntax"> </span><span class="identifier-syntax">VerbAccepted</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">best_etype</span><span class="plain-syntax"> = </span><span class="identifier-syntax">VERB_PE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">jump</span><span class="plain-syntax"> </span><span class="identifier-syntax">GiveError</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> .</span><span class="identifier-syntax">VerbAccepted</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="comment-syntax">We now definitely have a verb, not a direction, whether we got here by the</span>
<span class="plain-syntax"> </span><span class="comment-syntax">"take ..." or "person, take ..." method. Get the meta flag for this verb:</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">meta</span><span class="plain-syntax"> = ((</span><span class="identifier-syntax">verb_word</span><span class="plain-syntax">->#</span><span class="identifier-syntax">dict_par1</span><span class="plain-syntax">) & </span><span class="constant-syntax">2</span><span class="plain-syntax">)/2;</span>
<span class="plain-syntax"> </span><span class="comment-syntax">You can't order other people to "full score" for you, and so on...</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">meta</span><span class="plain-syntax"> == </span><span class="constant-syntax">1</span><span class="plain-syntax"> && </span><span class="identifier-syntax">actor</span><span class="plain-syntax"> ~= </span><span class="identifier-syntax">player</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">best_etype</span><span class="plain-syntax"> = </span><span class="identifier-syntax">VERB_PE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">meta</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">jump</span><span class="plain-syntax"> </span><span class="identifier-syntax">GiveError</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="comment-syntax">Now let i be the corresponding verb number...</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="identifier-syntax">DictionaryWordToVerbNum</span><span class="plain-syntax">(</span><span class="identifier-syntax">verb_word</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="comment-syntax">...then look up the i-th entry in the verb table, whose address is at word</span>
<span class="plain-syntax"> </span><span class="comment-syntax">7 in the Z-machine (in the header), so as to get the address of the syntax</span>
<span class="plain-syntax"> </span><span class="comment-syntax">table for the given verb...</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifdef</span><span class="plain-syntax"> </span><span class="identifier-syntax">TARGET_ZCODE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">syntax</span><span class="plain-syntax"> = (</span><span class="identifier-syntax">HDR_STATICMEMORY</span><span class="plain-syntax">-->0)--></span><span class="identifier-syntax">i</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifnot</span><span class="plain-syntax">; </span><span class="comment-syntax">TARGET_GLULX</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">syntax</span><span class="plain-syntax"> = (#</span><span class="identifier-syntax">grammar_table</span><span class="plain-syntax">)-->(</span><span class="identifier-syntax">i</span><span class="plain-syntax">+1);</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Endif</span><span class="plain-syntax">; </span><span class="comment-syntax">TARGET_</span>
<span class="plain-syntax"> </span><span class="comment-syntax">...and then see how many lines (ie, different patterns corresponding to the</span>
<span class="plain-syntax"> </span><span class="comment-syntax">same verb) are stored in the parse table...</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">num_lines</span><span class="plain-syntax"> = (</span><span class="identifier-syntax">syntax</span><span class="plain-syntax">->0) - </span><span class="constant-syntax">1</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="comment-syntax">...and now go through them all, one by one.</span>
<span class="plain-syntax"> </span><span class="comment-syntax">To prevent pronoun_word 0 being misunderstood,</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">pronoun_word</span><span class="plain-syntax"> = </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">; </span><span class="identifier-syntax">pronoun_obj</span><span class="plain-syntax"> = </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifdef</span><span class="plain-syntax"> </span><span class="identifier-syntax">DEBUG</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">parser_trace</span><span class="plain-syntax"> >= </span><span class="constant-syntax">1</span><span class="plain-syntax">)</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">print</span><span class="plain-syntax"> </span><span class="string-syntax">"[Parsing for the verb '"</span><span class="plain-syntax">, (</span><span class="identifier-syntax">address</span><span class="plain-syntax">) </span><span class="identifier-syntax">verb_word</span><span class="plain-syntax">, </span><span class="string-syntax">"' ("</span><span class="plain-syntax">, </span><span class="identifier-syntax">num_lines</span><span class="plain-syntax">+1, </span><span class="string-syntax">" lines)]^"</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Endif</span><span class="plain-syntax">; </span><span class="comment-syntax">DEBUG</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">best_etype</span><span class="plain-syntax"> = </span><span class="identifier-syntax">STUCK_PE</span><span class="plain-syntax">; </span><span class="identifier-syntax">nextbest_etype</span><span class="plain-syntax"> = </span><span class="identifier-syntax">STUCK_PE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">multiflag</span><span class="plain-syntax"> = </span><span class="reserved-syntax">false</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="comment-syntax">"best_etype" is the current failure-to-match error - it is by default</span>
<span class="plain-syntax"> </span><span class="comment-syntax">the least informative one, "don't understand that sentence".</span>
<span class="plain-syntax"> </span><span class="comment-syntax">"nextbest_etype" remembers the best alternative to having to ask a</span>
<span class="plain-syntax"> </span><span class="comment-syntax">scope token for an error message (i.e., the best not counting ASKSCOPE_PE).</span>
<span class="plain-syntax"> </span><span class="comment-syntax">multiflag is used here to prevent inappropriate MULTI_PE errors</span>
<span class="plain-syntax"> </span><span class="comment-syntax">in addition to its unrelated duties passing information to action routines</span>
</pre>
<p class="commentary firstcommentary"><a id="SP16" class="paragraph-anchor"></a><b>§16. Parser Letter E. </b>Break down a syntax line into analysed tokens.
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax"> </span><span class="identifier-syntax">line_address</span><span class="plain-syntax"> = </span><span class="identifier-syntax">syntax</span><span class="plain-syntax"> + </span><span class="constant-syntax">1</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">for</span><span class="plain-syntax"> (</span><span class="identifier-syntax">line</span><span class="plain-syntax">=0 : </span><span class="identifier-syntax">line</span><span class="plain-syntax"><=</span><span class="identifier-syntax">num_lines</span><span class="plain-syntax"> : </span><span class="identifier-syntax">line</span><span class="plain-syntax">++) {</span>
<span class="plain-syntax"> </span><span class="comment-syntax">Unpack the syntax line from Inform format into three arrays; ensure that</span>
<span class="plain-syntax"> </span><span class="comment-syntax">the sequence of tokens ends in an ENDIT_TOKEN.</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">line_address</span><span class="plain-syntax"> = </span><span class="identifier-syntax">UnpackGrammarLine</span><span class="plain-syntax">(</span><span class="identifier-syntax">line_address</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Ifdef</span><span class="plain-syntax"> </span><span class="identifier-syntax">DEBUG</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">parser_trace</span><span class="plain-syntax"> >= </span><span class="constant-syntax">1</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">parser_trace</span><span class="plain-syntax"> >= </span><span class="constant-syntax">2</span><span class="plain-syntax">) </span><span class="reserved-syntax">new_line</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">print</span><span class="plain-syntax"> </span><span class="string-syntax">"[line "</span><span class="plain-syntax">, </span><span class="identifier-syntax">line</span><span class="plain-syntax">; </span><span class="identifier-syntax">DebugGrammarLine</span><span class="plain-syntax">();</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">print</span><span class="plain-syntax"> </span><span class="string-syntax">"]^"</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> #</span><span class="identifier-syntax">Endif</span><span class="plain-syntax">; </span><span class="comment-syntax">DEBUG</span>
<span class="plain-syntax"> </span><span class="comment-syntax">We aren't in "not holding" or inferring modes, and haven't entered</span>
<span class="plain-syntax"> </span><span class="comment-syntax">any parameters on the line yet, or any special numbers; the multiple</span>
<span class="plain-syntax"> </span><span class="comment-syntax">object is still empty.</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">inferfrom</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">parameters</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nsns</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">; </span><span class="identifier-syntax">special_word</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">multiple_object</span><span class="plain-syntax">-->0 = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">multi_context</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">etype</span><span class="plain-syntax"> = </span><span class="identifier-syntax">STUCK_PE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="comment-syntax">Put the word marker back to just after the verb</span>