Provided by: libverilog-perl_3.418-1_amd64 
NAME
Verilog::Parser - Parse Verilog language files
SYNOPSIS
use Verilog::Parser;
my $parser = new Verilog::Parser;
$string = $parser->unreadback ();
$line = $parser->lineno ();
$parser->parse ($text)
$parser->parse_file ($filename)
DESCRIPTION
Verilog::Parser will tokenize a Verilog file when the parse() method is called and invoke
various callback methods. This is useful for extracting information and editing files
while retaining all context. For netlist like extractions, see Verilog::Netlist.
See the "Which Package" section of Verilog::Language if you are unsure which parsing
package to use for a new application.
Note the parser allows some constructs that are syntax errors according to the
specification (for example "foo.bar(1)++".) This is done when the parser can't easily
detect these cases. It's up to the consumer of the parser to filter out such errors if it
cares.
METHODS
$parser = Verilog::Parser->new (args...)
Create a new Parser.
Adding "symbol_table => []" will use the specified symbol table for this parse, and
modify the array reference to include those symbols detected by this parse. As the
SystemVerilog language requires packages and typedefs to exist before they are
referenced, you must pass the same symbol_table to subsequent parses that are for the
same compilation scope. The internals of this symbol_table should be considered
opaque, as it will change between package versions, and must not be modified by user
code.
Adding "use_cb_{callback-name} => 0" will disable the specified callback. By default,
all callbacks will be called; disabling callbacks can greatly speed up the parser as a
large percentage of time is spent calling between C and Perl to invoke the callbacks.
When using this feature, use_unreadback=>0 should be used too, as since whole tokens
are skipped, skipping whitespace shouldn't matter either.
Adding "use_protected => 0" will disable callbacks on `protected regions, which may
improve performance.
Adding "use_std => 1" will add parsing of the SystemVerilog built-in std:: package, or
"use_std => 0" will disable it. If unspecified it is silently included (no callbacks
will be involed) when suspected to be necessary.
Adding "use_unreadback => 0" will disable later use of the unreadback method, which
may improve performance.
Adding "use_vars => 0" will disable contassign, defparam, pin, var and port callbacks
to Verilog::SigParser. This can greatly speed parsing when variable and interconnect
information is not required.
$parser->callback_names ()
Return an array of callback function names. This may be used to automatically create
callbacks for all functions, or to test for different callback functionality between
versions of Verilog-Perl.
$parser->eof ()
Indicate the end of the input stream. All incomplete tokens will be parsed and all
remaining callbacks completed.
$parser->filename ($set)
Return (if $set is undefined) or set current filename.
$parser->lineno ($set)
Return (if $set is undefined) or set current line number.
$parser->parse ($string)
Parse the $string as verilog text. Can be called multiple times. Note not all
callbacks may be invoked until the eof method is called.
$parser->parse_file ($filename);
This method can be called to parse text from a file. The argument can be a filename
or an already opened file handle. The return value from parse_file() is a reference to
the parser object.
$parser->parse_preproc_file ($preproc);
This method can be called to parse preprocessed text from a predeclared
Verilog::Preproc object.
$parser->unreadback ($string)
Return any input string from the file that has not been sent to the callback. This
will include whitespace and tokens which did not have a callback. (For example
comments, if there is no comment callback.) This is useful for recording the entire
contents of the input, for preprocessors, pretty-printers, and such.
With the optional argument, set the text to be returned with the next unreadback call.
See also unreadbackCat, which is much faster.
To use this option, "use_unreadback => 1" must have been passed to the constructor.
$parser->unreadbackCat ($text)
Add text to be returned with the next unreadback call. This is much faster than using
"$parser->unreadback($parser->unreadback . $text)".
CALLBACKS
In order to make the parser do anything interesting, you must make a subclass where you
override one or more of the following callback methods as appropriate.
$self->attribute ( $token )
This method is called when any text in (* *) are recognized. The first argument,
$token, is the contents of the attribute including the delimiters.
$self->comment ( $token )
This method is called when any text in // or /**/ comments are recognized. The first
argument, $token, is the contents of the comment including the comment delimiters.
$self->endparse ( $token )
This method is called when the file has been completely parsed, at the End-Of-File of
the parsed file. It is useful for writing clean up routines.
$self->keyword ( $token )
This method is called when any Verilog keyword is recognized. The first argument,
$token, is the keyword.
$self->number ( $token )
This method is called when any number is recognized. The first argument, $token, is
the number. The Verilog::Language::number_value function may be useful for converting
a Verilog value to a Perl integer.
$self->operator ( $token )
This method is called when any symbolic operator (+, -, etc) is recognized. The first
argument, $token, is the operator.
$self->preproc ( $token )
This method is called when any Verilog preprocessor `command is recognized. Most of
these are handled by the preprocessor, however any unrecognized `defines are passed
through. For backward compatibility, if not defined this function will call the
symbol callback.
$self->string ( $token )
This method is called when any text in double quotes are recognized, or on the text of
protected regions. The first argument, $token, is the contents of the string
including the quotes.
$self->symbol ( $token )
This method is called when any Verilog symbol is recognized. A symbol is considered a
non-keyword bare-word. The first argument, $token, is the symbol.
$self->sysfunc ( $token )
This method is called when any Verilog $syscall is recognized. The first argument,
$token, is the symbol. For backward compatibility, if not defined this function will
call the symbol callback.
EXAMPLE
Here's a simple example which will print every symbol in a verilog file.
package MyParser;
use Verilog::Parser;
@ISA = qw(Verilog::Parser);
# parse, parse_file, etc are inherited from Verilog::Parser
sub new {
my $class = shift;
#print "Class $class\n";
my $self = $class->SUPER::new();
bless $self, $class;
return $self;
}
sub symbol {
my $self = shift;
my $token = shift;
$self->{symbols}{$token}++;
}
sub report {
my $self = shift;
foreach my $sym (sort keys %{$self->{symbols}}) {
printf "Symbol %-30s occurs %4d times\n",
$sym, $self->{symbols}{$sym};
}
}
package main;
my $parser = MyParser->new();
$parser->parse_file (shift);
$parser->report();
BUGS
This is being distributed as a baseline for future contributions. Don't expect a lot, the
Parser is still naive, and there are many awkward cases that aren't covered.
The parser currently assumes the string it is passed ends on a newline boundary. It
should be changed to allow arbitrary chunks.
Cell instantiations without any arguments are not supported, an empty set of parenthesis
are required. (Use "cell cell();", not "cell cell;".)
DISTRIBUTION
Verilog-Perl is part of the <http://www.veripool.org/> free Verilog EDA software tool
suite. The latest version is available from CPAN and from
<http://www.veripool.org/verilog-perl>.
Copyright 2000-2016 by Wilson Snyder. This package is free software; you can redistribute
it and/or modify it under the terms of either the GNU Lesser General Public License
Version 3 or the Perl Artistic License Version 2.0.
AUTHORS
Wilson Snyder <wsnyder@wsnyder.org>
SEE ALSO
Verilog-Perl, Verilog::Preproc, Verilog::SigParser, Verilog::Language, Verilog::Netlist,
Verilog::Getopt, vrename, vpassert vppreproc