use strict;
use warnings;
use Parse::RecDescent;

my $decommendedText = '';

sub concat ($) {$decommendedText .= $_[0]; 1;}

my $decomment = <<'GRAMMAR';
file : block(s)

block   : string
            {::concat ($item{string}); 1}
        | m{((?!/\*|"|').)+}s
            {::concat ($item[-1]); 1}
        | comment
            {::concat ($item{comment}); 1;}
            
string  : /"([^"]|\\")*"/
            {$return = $item[-1] . ($text =~ /^\n/ ? "\n" : ''); 1;}
        | /'([^']|\\')*'/
            {$return = $item[-1] . ($text =~ /^\n/ ? "\n" : ''); 1;}
        
comment : '/*' commentBlock '*/'
            {$return = $text =~ /^\n/ ? "\n" : ''; 1;}

commentBlock   :  m{((?! \*/ | /\* ).)*}sx comment m{((?! \*/ | /\* ).)*}sx
            {$return = "\n"; 1;}
        | m{((?! \*/ | /\* ).)+}sx
            {$return = ''; 1;}

GRAMMAR


my $parse = new Parse::RecDescent ($decomment);

my $input = <<'DATA';
#include "StdAfx.h" // Tail comment
#include "Utility\perftime.h"
#pragma hdrstop

/* Comment before MACRO */
/* Comment /* and nested comment */ lines */

#define MACRO 10\
              + 3 // Multi line macro with comment

#define __DEBUG /* comment */ 1
#define STRING 'This is a string' /* comment */
#define COMMENT "/* comment in \"a\" string */"

// c++ comment line
/* Comment at start for a number of lines */
/* multi-line comment
/* nested */
block */
// cpp block

char PerfTimer::Buf[64];
DATA

$parse->file($input) or die "Parse failed\n";
print $decommendedText;