Re: How do I match/extract a function from a JavaScript file?

[Shakya]

Following definitely works in "not so complex" scenarios

#!/usr/bin/perl
use strict;

my $Jscript = join (" ",<DATA>);
# Extract function foo from Jscript
my $content = _extract("foo",$Jscript);

sub _extract {
    my ($funct,$Jscript) = @_;

    my ($round,$curly);
    $round = qr!\(([^()]*|(??{$round}))*\)!;
    $curly = qr!\{([^{}]*|(??{$curly}))*\}!;

    if ($Jscript =~ m!($funct\s*$round\s*$curly)!ms) {
        print "Matched :\n",$1;
    } 
}

__DATA__

foo (a, b, c) {
  if (c) { a++; } else { b--; }
  print "hi";
}
fum (d, e, f, g, h) {
  if (d) { e++; } else { f = g + h; }
  print "ho";
}

Output is :

Matched :
foo (a, b, c) {
   if (c) { a++; } else { b--; }
   print "hi";
}

On more explanation on matching nested parentheses, you can refer Friedl's Mastering Regular Expressions, page 330.

[erroneousBollock]

  sub _extract {
    my ($funct,$Jscript) = @_;

    my ($round,$curly);
    $round = qr!\(([^()]*|(??{$round}))*\)!;
    $curly = qr!\{([^{}]*|(??{$curly}))*\}!;

    if ($Jscript =~ m!($funct\s*$round\s*$curly)!ms) {
        print "Matched :\n",$1;
    } 
  }

err, I can't see where you've matched the function keyword or the function operator anywhere in your code. That would seem to be a prerequisite to parsing out functions from ECMAScript source.

  foo (a, b, c) {
    if (c) { a++; } else { b--; }
    print "hi";
  }
  fum (d, e, f, g, h) {
    if (d) { e++; } else { f = g + h; }
    print "ho";
  }

That's not valid EMCAScript.

-David.