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Verilog::Language - Verilog language utilities


  use Verilog::Language;

  $result = Verilog::Language::is_keyword ("wire");  # true
  $result = Verilog::Language::is_compdirect ("`notundef");  # false
  $result = Verilog::Language::number_value ("4'b111");  # 8
  $result = Verilog::Language::number_bits  ("32'h1b");  # 32
  $result = Verilog::Language::number_signed ("1'sh1");  # 1
  @vec    = Verilog::Language::split_bus ("[31,5:4]"); # 31, 5, 4
  @vec    = Verilog::Language::split_bus_nocomma ("[31:29]"); # 31, 30, 29
  $result = Verilog::Language::strip_comments ("a/*b*/c");  # ac


Verilog::Language provides general utilities for using the Verilog Language, such as parsing numbers or determining what keywords exist. General functions will be added as needed.


Verilog::Language::is_keyword ($symbol_string)

Return true if the given symbol string is a Verilog reserved keyword. Value indicates the language standard as per the `begin_keywords macro, '1364-1995', '1364-2001', '1364-2005', '1800-2005', '1800-2009', '1800-2012' or 'VAMS'.

Verilog::Language::is_compdirect ($symbol_string)

Return true if the given symbol string is a Verilog compiler directive.

Verilog::Language::is_gateprim ($symbol_string)

Return true if the given symbol is a built in gate primitive; for example "buf", "xor", etc.

Verilog::Language::language_keywords ($year)

Returns a hash for keywords for given language standard year, where the value of the hash is the standard in which it was defined.

Verilog::Language::language_standard ($year)

Sets the language standard to indicate what are keywords. If undef, all standards apply. The year is indicates the language standard as per the `begin_keywords macro, '1364-1995', '1364-2001', '1364-2005', '1800-2005' '1800-2009' or '1800-2012'.


Returns the greatest language currently standardized, presently '1800-2012'.

Verilog::Language::number_bigint ($number_string)

Return the numeric value of a Verilog value stored as a Math::BigInt, or undef if incorrectly formed. You must 'use Math::BigInt' yourself before calling this function. Note bigints do not have an exact size, so NOT of a Math::BigInt may return a different value than verilog. See also number_value and number_bitvector.

Verilog::Language::number_bits ($number_string)

Return the number of bits in a value string, or undef if incorrectly formed, _or_ not specified.

Verilog::Language::number_bitvector ($number_string)

Return the numeric value of a Verilog value stored as a Bit::Vector, or undef if incorrectly formed. You must 'use Bit::Vector' yourself before calling this function. The size of the Vector will be that returned by number_bits.

Verilog::Language::number_signed ($number_string)

Return true if the Verilog value is signed, else undef.

Verilog::Language::number_value ($number_string)

Return the numeric value of a Verilog value, or undef if incorrectly formed. It ignores any signed Verilog attributes, but is is returned as a perl signed integer, so it may fail for over 31 bit values. See also number_bigint and number_bitvector.

Verilog::Language::split_bus ($bus)

Return a list of expanded arrays. When passed a string like "foo[5:1:2,10:9]", it will return a array with ("foo[5]", "foo[3]", ...). It correctly handles connectivity expansion also, so that "x[1:0] = y[3:0]" will get intuitive results.

Verilog::Language::split_bus_nocomma ($bus)

As with split_bus, but faster. Only supports simple decimal colon separated array specifications, such as "foo[3:0]".

Verilog::Language::strip_comments ($text)

Return text with any // or /**/ comments stripped, correctly handing quoted strings. Newlines will be preserved in this process.


Verilog-Perl is part of the free Verilog EDA software tool suite. The latest version is available from CPAN and from

Copyright 2000-2017 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.


Wilson Snyder <>


Verilog-Perl, Verilog::EditFiles Verilog::Parser, Verilog::ParseSig, Verilog::Getopt

And the package for Emacs.

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