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.
34 Adding "symbol_table => []" will use the specified symbol table for
36 this parse, and modify the array reference to include those symbols
37 detected by this parse. As the SystemVerilog language requires
38 packages and typedefs to exist before they are referenced, you must
39 pass the same symbol_table to subsequent parses that are for the
40 same compilation scope. The internals of this symbol_table should
41 be considered opaque, as it will change between package versions,
42 and must not be modified by user code.
43 Adding "use_cb_{callback-name} => 0" will disable the specified
45 callback. By default, all callbacks will be called; disabling
46 callbacks can greatly speed up the parser as a large percentage of
47 time is spent calling between C and Perl to invoke the callbacks.
48 When using this feature, use_unreadback=>0 should be used too, as
49 since whole tokens are skipped, skipping whitespace shouldn't
50 matter either.
51 Adding "use_std => 1" will add parsing of the SystemVerilog built-
53 in std:: package, or "use_std => 0" will disable it. If
54 unspecified it is silently included (no callbacks will be involed)
55 when suspected to be necessary.
56 Adding "use_unreadback => 0" will disable later use of the
58 unreadback method, which may improve performance.
59 Adding "use_vars => 0" will disable contassign, defparam, pin, var
61 and port callbacks to Verilog::SigParser. This can greatly speed
62 parsing when variable and interconnect information is not required.
63 $parser->callback_names ()
65 Return an array of callback function names. This may be used to
66 automatically create callbacks for all functions, or to test for
67 different callback functionality between versions of Verilog-Perl.
68 $parser->eof ()
70 Indicate the end of the input stream. All incomplete tokens will
71 be parsed and all remaining callbacks completed.
72 $parser->filename ($set)
74 Return (if $set is undefined) or set current filename.
75 $parser->lineno ($set)
77 Return (if $set is undefined) or set current line number.
78 $parser->parse ($string)
80 Parse the $string as verilog text. Can be called multiple times.
81 Note not all callbacks may be invoked until the eof method is
82 called.
83 $parser->parse_file ($filename);
85 This method can be called to parse text from a file. The argument
86 can be a filename or an already opened file handle. The return
87 value from parse_file() is a reference to the parser object.
88 $parser->parse_preproc_file ($preproc);
90 This method can be called to parse preprocessed text from a
91 predeclared Verilog::Preproc object.
92 $parser->unreadback ($string)
94 Return any input string from the file that has not been sent to the
95 callback. This will include whitespace and tokens which did not
96 have a callback. (For example comments, if there is no comment
97 callback.) This is useful for recording the entire contents of the
98 input, for preprocessors, pretty-printers, and such.
99 With the optional argument, set the text to be returned with the
101 next unreadback call. See also unreadbackCat, which is much
102 faster.
103 To use this option, "use_unreadback => 1" must have been passed to
105 the constructor.
106 $parser->unreadbackCat ($text)
108 Add text to be returned with the next unreadback call. This is
109 much faster than using "$parser->unreadback($parser->unreadback .
110 $text)".
111
113 In order to make the parser do anything interesting, you must make a
114 subclass where you override one or more of the following callback
115 methods as appropriate.
116 $self->attribute ( $token )
118 This method is called when any text in (* *) are recognized. The
119 first argument, $token, is the contents of the attribute including
120 the delimiters.
121 $self->comment ( $token )
123 This method is called when any text in // or /**/ comments are
124 recognized. The first argument, $token, is the contents of the
125 comment including the comment delimiters.
126 $self->endparse ( $token )
128 This method is called when the file has been completely parsed, at
129 the End-Of-File of the parsed file. It is useful for writing clean
130 up routines.
131 $self->keyword ( $token )
133 This method is called when any Verilog keyword is recognized. The
134 first argument, $token, is the keyword.
135 $self->number ( $token )
137 This method is called when any number is recognized. The first
138 argument, $token, is the number. The
139 Verilog::Language::number_value function may be useful for
140 converting a Verilog value to a Perl integer.
141 $self->operator ( $token )
143 This method is called when any symbolic operator (+, -, etc) is
144 recognized. The first argument, $token, is the operator.
145 $self->preproc ( $token )
147 This method is called when any Verilog preprocessor `command is
148 recognized. Most of these are handled by the preprocessor, however
149 any unrecognized `defines are passed through. For backward
150 compatibility, if not defined this function will call the symbol
151 callback.
152 $self->string ( $token )
154 This method is called when any text in double quotes are
155 recognized, or on the text of protected regions. The first
156 argument, $token, is the contents of the string including the
157 quotes.
158 $self->symbol ( $token )
160 This method is called when any Verilog symbol is recognized. A
161 symbol is considered a non-keyword bare-word. The first argument,
162 $token, is the symbol.
163 $self->sysfunc ( $token )
165 This method is called when any Verilog $syscall is recognized. The
166 first argument, $token, is the symbol. For backward compatibility,
167 if not defined this function will call the symbol callback.
168
170 Here's a simple example which will print every symbol in a verilog
171 file.
172 package MyParser;
174 use Verilog::Parser;
175 @ISA = qw(Verilog::Parser);
176 # parse, parse_file, etc are inherited from Verilog::Parser
178 sub new {
179 my $class = shift;
180 #print "Class $class\n";
181 my $self = $class->SUPER::new();
182 bless $self, $class;
183 return $self;
184 }
185 sub symbol {
187 my $self = shift;
188 my $token = shift;
189 $self->{symbols}{$token}++;
191 }
192 sub report {
194 my $self = shift;
195 foreach my $sym (sort keys %{$self->{symbols}}) {
197 printf "Symbol %-30s occurs %4d times\n",
198 $sym, $self->{symbols}{$sym};
199 }
200 }
201 package main;
203 my $parser = MyParser->new();
205 $parser->parse_file (shift);
206 $parser->report();
207
209 This is being distributed as a baseline for future contributions.
210 Don't expect a lot, the Parser is still naive, and there are many
211 awkward cases that aren't covered.
212 The parser currently assumes the string it is passed ends on a newline
214 boundary. It should be changed to allow arbitrary chunks.
215 Cell instantiations without any arguments are not supported, an empty
217 set of parenthesis are required. (Use "cell cell();", not "cell
218 cell;".)
219
221 Verilog-Perl is part of the <http://www.veripool.org/> free Verilog EDA
222 software tool suite. The latest version is available from CPAN and
223 from http://www.veripool.org/verilog-perl
224 <http://www.veripool.org/verilog-perl>.
225 Copyright 2000-2010 by Wilson Snyder. This package is free software;
227 you can redistribute it and/or modify it under the terms of either the
228 GNU Lesser General Public License Version 3 or the Perl Artistic
229 License Version 2.0.
230
232 Wilson Snyder <wsnyder@wsnyder.org>
233
235 Verilog-Perl, Verilog::Preproc, Verilog::SigParser, Verilog::Language,
236 Verilog::Netlist, Verilog::Getopt, vrename, vpassert vppreproc
237perl v5.12.2 2010-10-25 Parser(3)