Filter::Trigraph - understand ANSI C trigraphs in Perl source.


  use Filter::Trigraph;

  my $x = shift??!??!"testing";
    ??= uppercase all vowels in $x
    ??= uppercase all non-vowels in $x
  print "$x??/n";


Now that Perl supports Unicode, we should also support ISO 646-1983.

ISO 646 is a character set very like ASCII, but with 9 of you favourite characters removed.

ANSI C supports this limited character set using a wonderful system called "trigraphs" that replace the 9 missing essential characters with sequences of two question marks and another symbol.

Using this module you can now write Perl using only the characters found in ISO 646.


Search for brain-damage in your local GNU C documentation.


Marty Pauley <>


Copyright (C) 2001 Marty Pauley.

This program is free software; you can redistribute it and/or modify it under the terms of either:

a) the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. b) the Perl Artistic License.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.