#!/usr/local/bin/perl -ws
# REMOVE COMMENTS FROM C++ CODE
# ORIGINAL BY Helmut Jarausch
# EXTENDED BY Damian Conway AND Helmut Jarausch
use strict;
use Parse::RecDescent;
use vars qw/ $Grammar /;
my $parser = new Parse::RecDescent $Grammar  or  die "invalid grammar";
undef $/;
my $text = @ARGV ? <> : <DATA>;
$parser->program($text) or die "malformed C program";
print "Comments\n========\n$parser->{comments}\n";
print "\nCode\n====\n$parser->{code}\n";
print "\nStrings\n=======\n", map(qq{\t"$_"\n}, @{$parser->{strings}});
BEGIN
{ $Grammar=<<'EOF';
program : <skip:''> { @{$thisparser}{qw(comments code strings)} = () }
          part(s)
part    : comment { $thisparser->{comments} .= $item[1];
                    $thisparser->{code}     .= " "; }
        | C_code  { $thisparser->{code}     .= $item[1]; }
        | string  { $thisparser->{code}     .= qq("$item[1]");
                    push @{$thisparser->{strings}}, $item[1]; }
C_code  : m{(
              [^"/]+            # one or more non-delimiters
              (                 # then (optionally)...
               /                # a potential comment delimiter
               [^*/]            # which is not an actual delimiter
              )?                #
            )+                  # all repeated once or more
           }x
string  : m{"                   # a leading delimiter
            ((                  # zero or more...
              \\.               # escaped anything
              |                 # or
              [^"]              # anything but a delimiter
             )*
            )
            "}x
                { $return =  $1 }
comment : m{\s*                 # optional whitespace
            //                  # comment delimiter
            [^\n]*              # anything except a newline
            \n                  # then a newline
           }x
        | m{\s*                 # optional whitespace
            /\*                 # comment opener
            (?:[^*]+|\*(?!/))*  # anything except */
            \*/                 # comment closer
            ([ \t]*)?           # trailing blanks or tabs
           }x
EOF
}
__DATA__
program test; // for decomment
// using Parse::RecDescent
int main()
{
/* this should
   be removed
*/
  char *cp1 = "";
  char *cp2 = "cp2";
  int i;  // a counter
          // remove this line altogehter
  int k;
      int more_indented;  // keep indentation
      int l;  /* a loop
             variable */
      // should be completely removed
  char *str = "/* ceci n'est pas un commentaire */";
  return 0;
}