1Parser(3) User Contributed Perl Documentation Parser(3)
2
6 Verilog::Parser - Parse Verilog language files
7
9 use Verilog::Parser;
10 my $parser = new Verilog::Parser;
12 $string = $parser->unreadback ();
13 $line = $parser->lineno ();
14 $parser->parse ($text)
15 $parser->parse_file ($filename)
16
18 Verilog::Parser will tokenize a Verilog file when the parse() method is
19 called and invoke various callback methods. This is useful for
20 extracting information and editing files while retaining all context.
21 For netlist like extractions, see Verilog::Netlist.
22 See the "Which Package" section of Verilog::Language if you are unsure
24 which parsing package to use for a new application.
25 Note the parser allows some constructs that are syntax errors according
27 to the specification (for example "foo.bar(1)++".) This is done when
28 the parser can't easily detect these cases. It's up to the consumer of
29 the parser to filter out such errors if it cares.
30
32 $parser = Verilog::Parser->new (args...)
33 Create a new Parser. Passing the named argument "use_unreadback =>
34 0" will disable later use of the unreadback method, which may
35 improve performance.
36 Adding "use_std => 1" will add parsing of the SystemVerilog built-
38 in std:: package, or "use_std => 0" will disable it. If
39 unspecified it is silently included (no callbacks will be involed)
40 when suspected to be necessary.
41 Adding "symbol_table => []" will use the specified symbol table for
43 this parse, and modify the array reference to include those symbols
44 detected by this parse. As the SystemVerilog language requires
45 packages and typedefs to exist before they are referenced, you must
46 pass the same symbol_table to subsequent parses that are for the
47 same compilation scope. The internals of this symbol_table should
48 be considered opaque, as it will change between package versions,
49 and must not be modified by user code.
50 $parser->callback_names ()
52 Return an array of callback function names. This may be used to
53 automatically create callbacks for all functions, or to test for
54 different callback functionality between versions of Verilog-Perl.
55 $parser->eof ()
57 Indicate the end of the input stream. All incomplete tokens will
58 be parsed and all remaining callbacks completed.
59 $parser->filename ($set)
61 Return (if $set is undefined) or set current filename.
62 $parser->lineno ($set)
64 Return (if $set is undefined) or set current line number.
65 $parser->parse ($string)
67 Parse the $string as verilog text. Can be called multiple times.
68 Note not all callbacks may be invoked until the eof method is
69 called.
70 $parser->parse_file ($filename);
72 This method can be called to parse text from a file. The argument
73 can be a filename or an already opened file handle. The return
74 value from parse_file() is a reference to the parser object.
75 $parser->parse_preproc_file ($preproc);
77 This method can be called to parse preprocessed text from a
78 predeclared Verilog::Preproc object.
79 $parser->unreadback ($string)
81 Return any input string from the file that has not been sent to the
82 callback. This will include whitespace and tokens which did not
83 have a callback. (For example comments, if there is no comment
84 callback.) This is useful for recording the entire contents of the
85 input, for preprocessors, pretty-printers, and such.
86 With the optional argument, set the text to be returned with the
88 next unreadback call. See also unreadbackCat, which is much
89 faster.
90 To use this option, "use_unreadback => 1" must have been passed to
92 the constructor.
93 $parser->unreadbackCat ($text)
95 Add text to be returned with the next unreadback call. This is
96 much faster than using "$parser->unreadback($parser->unreadback .
97 $text)".
98
100 In order to make the parser do anything interesting, you must make a
101 subclass where you override one or more of the following callback
102 methods as appropriate.
103 $self->attribute ( $token )
105 This method is called when any text in (* *) are recognized. The
106 first argument, $token, is the contents of the attribute including
107 the delimiters.
108 $self->comment ( $token )
110 This method is called when any text in // or /**/ comments are
111 recognized. The first argument, $token, is the contents of the
112 comment including the comment delimiters.
113 $self->endparse ( $token )
115 This method is called when the file has been completely parsed, at
116 the End-Of-File of the parsed file. It is useful for writing clean
117 up routines.
118 $self->keyword ( $token )
120 This method is called when any Verilog keyword is recognized. The
121 first argument, $token, is the keyword.
122 $self->number ( $token )
124 This method is called when any number is recognized. The first
125 argument, $token, is the number. The
126 Verilog::Language::number_value function may be useful for
127 converting a Verilog value to a Perl integer.
128 $self->operator ( $token )
130 This method is called when any symbolic operator (+, -, etc) is
131 recognized. The first argument, $token, is the operator.
132 $self->preproc ( $token )
134 This method is called when any Verilog preprocessor `command is
135 recognized. Most of these are handled by the preprocessor, however
136 any unrecognized `defines are passed through. For backward
137 compatibility, if not defined this function will call the symbol
138 callback.
139 $self->string ( $token )
141 This method is called when any text in double quotes are
142 recognized, or on the text of protected regions. The first
143 argument, $token, is the contents of the string including the
144 quotes.
145 $self->symbol ( $token )
147 This method is called when any Verilog symbol is recognized. A
148 symbol is considered a non-keyword bare-word. The first argument,
149 $token, is the symbol.
150 $self->sysfunc ( $token )
152 This method is called when any Verilog $syscall is recognized. The
153 first argument, $token, is the symbol. For backward compatibility,
154 if not defined this function will call the symbol callback.
155
157 Here's a simple example which will print every symbol in a verilog
158 file.
159 package MyParser;
161 use Verilog::Parser;
162 @ISA = qw(Verilog::Parser);
163 # parse, parse_file, etc are inherited from Verilog::Parser
165 sub new {
166 my $class = shift;
167 #print "Class $class\n";
168 my $self = $class->SUPER::new();
169 bless $self, $class;
170 return $self;
171 }
172 sub symbol {
174 my $self = shift;
175 my $token = shift;
176 $self->{symbols}{$token}++;
178 }
179 sub report {
181 my $self = shift;
182 foreach my $sym (sort keys %{$self->{symbols}}) {
184 printf "Symbol %-30s occurs %4d times\n",
185 $sym, $self->{symbols}{$sym};
186 }
187 }
188 package main;
190 my $parser = MyParser->new();
192 $parser->parse_file (shift);
193 $parser->report();
194
196 This is being distributed as a baseline for future contributions.
197 Don't expect a lot, the Parser is still naive, and there are many
198 awkward cases that aren't covered.
199 The parser currently assumes the string it is passed ends on a newline
201 boundary. It should be changed to allow arbitrary chunks.
202 Cell instantiations without any arguments are not supported, an empty
204 set of parenthesis are required. (Use "cell cell();", not "cell
205 cell;".)
206
208 Verilog-Perl is part of the <http://www.veripool.org/> free Verilog EDA
209 software tool suite. The latest version is available from CPAN and
210 from http://www.veripool.org/verilog-perl
211 <http://www.veripool.org/verilog-perl>.
212 Copyright 2000-2009 by Wilson Snyder. This package is free software;
214 you can redistribute it and/or modify it under the terms of either the
215 GNU Lesser General Public License Version 3 or the Perl Artistic
216 License Version 2.0.
217
219 Wilson Snyder <wsnyder@wsnyder.org>
220
222 Verilog-Perl, Verilog::Preproc, Verilog::SigParser, Verilog::Language,
223 Verilog::Netlist, Verilog::Getopt, vrename, vpassert vppreproc
224perl v5.12.0 2009-07-20 Parser(3)