Add nonterminal syntax

Closes #8; closes #11; closes #10.
tc39 · Sep 26, 2014 · e32df12 · e32df12
1 parent 661ec92
commit e32df12
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Showing 6 changed files with 43 additions and 2 deletions.
diff --git a/README.md b/README.md
@@ -52,3 +52,5 @@ Every Ecmarkdown fragment is a **numeric list**. They are written as a series of
 **Strings** are written as `"x"` and are translated to `<code>"x"</code>`. (In other words, quoted strings are automatically interpreted as code, with no need to surround them in backticks.) Strings cannot contain double quotes.
 
 **Spec-level constants** are written as `~x~` and are translated to `<emu-const>x</emu-const>`. Spec-level constants cannot contain spaces or tildes.
+
+**Nonterminals** are written as `|x|`, `|x_opt|`, `|x[p]|`, or `|x[p]_opt|`. These are translated, respectively, into `<emu-nt>x</emu-nt>`, `<emu-nt optional>x</emu-nt>`, `<emu-nt params="p">x</emu-nt>`, or `<emu-nt params="p" optional>x</emu-nt>`. Nonterminal names can only be composed of letters. Params can be composed of anything except a closing square bracket.
diff --git a/lib/actions.js b/lib/actions.js
@@ -72,6 +72,20 @@ exports.specConstant = function (content) {
     return $('<emu-const>').text(content);
 };
 
+exports.nonterminal = function (name, params, opt) {
+    var nt = $('<emu-nt>').text(name);
+
+    if (params) {
+        nt.attr('params', params[1]);
+    }
+
+    if (opt) {
+        nt.attr('optional', '');
+    }
+
+    return nt;
+};
+
 exports.dents = function (spaces, state) {
     var indentDepths = state.indentDepths;
     var depth = spaces.length;

diff --git a/lib/beautify.js b/lib/beautify.js
@@ -6,7 +6,7 @@ module.exports = function beautify(html) {
     var originalOutput = beautifyWithBugs(html, {
         indent_size: 2,
         wrap_line_length: 0,
-        unformatted: ['emu-const', 'emu-val'].concat(inlineElements)
+        unformatted: ['emu-const', 'emu-val', 'emu-nt'].concat(inlineElements)
     });
 
     // https://github.com/beautify-web/js-beautify/issues/524
@@ -15,5 +15,8 @@ module.exports = function beautify(html) {
     // https://github.com/beautify-web/js-beautify/issues/525
     var fixExtraSpaces = fixNewlines.replace(/>  </g, '> <');
 
-    return fixExtraSpaces;
+    // Remove empty =""s
+    var withSimplifiedAttributes = fixExtraSpaces.replace(/=""/g, '');
+
+    return withSimplifiedAttributes;
 };
diff --git a/lib/grammar.pegjs b/lib/grammar.pegjs
@@ -14,6 +14,7 @@ atom = variable
      / string
      / value
      / specConstant
+     / nonterminal
      / normalText
 
 variable = "_" first:variableSegment rest:$("_" variableSegment &"_")* "_" { return actions.variable(first, rest); }
@@ -28,4 +29,7 @@ value = "*" content:$[^\n* ]+ "*"                                          { ret
 
 specConstant = "~" content:$[^\n~ ]+ "~"                                   { return actions.specConstant(content); }
 
+nonterminal = "|" name:$[a-z]i+ params:("[" $[^\]]+ "]")? opt:"_opt"? "|"  { return actions.nonterminal(name,
+                                                                                                        params, opt); }
+
 normalText = $[^\n]
diff --git a/test/cases/nonterminals.ecmarkdown b/test/cases/nonterminals.ecmarkdown
@@ -0,0 +1,8 @@
+0. |NonTerminalName|
+0. |NonTerminalName_opt|
+0. |NonTerminalName[Parameter1]|
+0. |NonTerminalName[Parameter1, ?Parameter2]_opt|
+0. at end |NonTerminalName[Parameter1, ?Parameter2]_opt|
+0. |NonTerminalName[Parameter1, ?Parameter2]_opt| at start
+0. in |NonTerminalName[Parameter1, ?Parameter2]_opt| middle
+0. invalid |NonTerminalName_opt[Parameter1, ?Parameter2]|
diff --git a/test/cases/nonterminals.html b/test/cases/nonterminals.html
@@ -0,0 +1,10 @@
+<ol>
+  <li><emu-nt>NonTerminalName</emu-nt></li>
+  <li><emu-nt optional>NonTerminalName</emu-nt></li>
+  <li><emu-nt params="Parameter1">NonTerminalName</emu-nt></li>
+  <li><emu-nt params="Parameter1, ?Parameter2" optional>NonTerminalName</emu-nt></li>
+  <li>at end <emu-nt params="Parameter1, ?Parameter2" optional>NonTerminalName</emu-nt></li>
+  <li><emu-nt params="Parameter1, ?Parameter2" optional>NonTerminalName</emu-nt> at start</li>
+  <li>in <emu-nt params="Parameter1, ?Parameter2" optional>NonTerminalName</emu-nt> middle</li>
+  <li>invalid |NonTerminalName_opt[Parameter1, ?Parameter2]|</li>
+</ol>