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59359ca @tewk [Pmc2c] Continued cleanup and reorg
tewk authored
1 =head1 NAME
2
3 tools/build/pmc2c.pl - PMC definition to C compiler
4
5 =head2 Internals
6
7 To see the internal data structures please run:
8
9 % perl tools/build/pmc2c.pl --c --debug --debug sarray.pmc | less
10
11 =head2 Compiling PMCs
12
13 First, the program determines the names of the .c and .h files from
14 the basename of the .pmc file (e.g. F<perlint.pmc> -> F<perlint.c> and
15 F<perlint.h>).
16
17 Next, the file is searched for C</pmclass \w*/> which attempts to find the
18 class being declared.
19
20 Once the class is found, all of its superclasses are scanned and their
21 methods added to the methods of the current PMC. PMCs default to
22 inheriting from 'default'. Only single inheritance is supported.
23
24 Once the superclass is determined, it is processed and its method names
25 are extracted and saved.
26
27 Next, each method body is processed with various directives (see below)
28 getting replaced by their appropriate values.
29
30 Finally, the .c and .h files are generated. The appropriate base class
31 header files are included.
32
30765f8 @particle [PDD17]: rename pmc definition modifier 'noinit' to 'no_init' for con…
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33 If the C<no_init> flag was used, then no init function is generated.
59359ca @tewk [Pmc2c] Continued cleanup and reorg
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34 Otherwise, one is generated which sets up the vtable and enters it into
35 the C<vtables> array.
36
37 The .c file is generated by appending the functions after the various
38 directives have been replaced.
39
40 =head2 PMC File Syntax
41
42 The basic syntax of a PMC file is
43
44 =over 4
45
46 =item 1.
47
48 A preamble, consisting of code to be copied directly to the .c file
49
50 =item 2.
51
52 The C<pmclass> declaration:
53
54 pmclass PMCNAME [flags] {
55
56 where C<flags> are:
57
58 =over 4
59
60 =item C<extends PMCPARENT>
61
62 All methods not defined in PMCNAME are inherited from the PMCPARENT class.
63 If no parent class is defined, methods from F<default.pmc> are used.
64
65 =item C<abstract>
66
67 This class cannot be instantiated. Abstract classes are shown with lower
68 case class names in the class tree.
69
30765f8 @particle [PDD17]: rename pmc definition modifier 'noinit' to 'no_init' for con…
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70 =item C<no_init>
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71
72 Used with C<abstract>: No C<class_init> code is generated.
73
74 =item C<const_too>
75
76 Classes with this flag get 2 vtables and 2 enums, one pair with
77 read/write set methods, and one with read-only set methods.
78
79 =item C<does interface>
80
81 The class 'does' the given interfaces (the collection of methods
82 which the class implements).
83
84 The default is "scalar". Other currently used interfaces are:
85
86 array : container PMC with numerically-keyed elements
87 event : PMC that can be used with event queue
88 hash : container PMC with string-keyed elements
89 library : PMC that corresponds to a dynamic library
90 ref : PMC that references another PMC
91 string : PMC that behaves similarly to the base string type
92 boolean : PMC that does true/false only.
93 integer : PMC that behaves similarly to the base int type
94 float : PMC that behaves similarly to the base number type
95 scalar : (only used by the sample src/dynpmc/foo.pmc)
96
97 This is not a canonical list, but merely a snapshot of what's in use.
98
99 =item C<dynpmc>
100
101 The class is a dynamic class. These have a special C<class_init>
102 routine suitable for dynamic loading at runtime. See the F<src/dynpmc>
103 directory for an example.
104
105 =item C<group GROUP>
106
107 The class is part of a group of interrelated PMCs that should be
108 compiled together into a single shared library of the given name. Only
109 valid for dynamic PMCs.
110
111 =item C<lib LIB>
112
113 The class needs an external library.
114
115 =item C<hll HLL>
116
117 The High level language this PMC corresponds to.
118
119 =item C<maps Type>
120
121 The basic parrot PMC type that this PMC correspond to for C<.HLL>
122 usage. For example:
123
b6641b0 @coke Resolve ticket #38168 ([TODO] - Tcl - :slurpy HLL mappings)
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124 pmclass TclInt hll Tcl maps Integer
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125
126 allows this PMC to automatically be used when autoboxing C<I> registers to PMCs.
127
b6641b0 @coke Resolve ticket #38168 ([TODO] - Tcl - :slurpy HLL mappings)
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128 Requires the C<hll> flag. Note that multiple mappings can be specified:
129
130 pmclass myOrderedHash hll frob maps Hash maps Array
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131
132 =back
133
134 =item 3.
135
136 A list of vtable method implementations
137
138 =item 4.
139
140 The final close C<}>
141
142 =back
143
144 =head2 Method Body Substitutions
145
146 The vtable method bodies can use the following substitutions:
147
148 =over 4
149
150 =item C<SELF>
151
152 Converted to the current PMC object of type C<PMC *>.
153
154 =item C<INTERP>
155
156 Converted to the interpreter object.
157
158 =item C<OtherClass.SELF.method(a,b,c)>
159
160 Calls the static vtable method 'method' in C<OtherClass>.
161
162 =item C<SELF.method(a,b,c)>
163
164 Calls the vtable method 'method' using the dynamic type of C<SELF>.
165
59661f1 @allisonrandal [pdd17pmc] Merging the pdd17pmc branch into trunk (r24435 to r26307).
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166 =item C<SELF(a,b,c)>
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167
168 Same as above, but calls the current method.
169
59661f1 @allisonrandal [pdd17pmc] Merging the pdd17pmc branch into trunk (r24435 to r26307).
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170 =item C<STATICSELF.method(a,b,c)>
171
172 Calls the vtable method 'method' using the static type of C<SELF> (in
173 other words, calls another method defined in the same file).
174
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175 =item C<OtherClass.SUPER(a,b,c)>
176
177 Calls the overridden implementation of the current method in
178 C<OtherClass>.
179
180 =item C<SUPER(a,b,c)>
181
182 Calls the overridden implementation of the current method in the nearest
ddce55e @cotto [pmc2c] rip out DYNSUPER, which isn't needed now that it and SUPER ac…
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183 superclass, using the type of C<SELF>.
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184
185 =back
186
187 =head1 AUTHOR
188
189 Leopold Toetsch.
190
191 Cleaned up by Matt Diephouse.
192
193 Many thanks to the author of F<pmc2c.pl>, many useful code pieces got
194 reused.
195
196 =cut
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