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In Murder of a Perl coder I commented that coding C# could be almost as much fun as coding Perl, at which point Jenda suggested that C# Regex support was vomit-inducing :)

I know there are a number of esteemed monks familiar with both Perl and C# so I thought it might be useful to open this discussion to a wider audience, especially since many Win32 monks can probably expect to face this comparison sooner or later, courtesy of the MS marketing juggernaut.

So here is a comparison of a tiny templating app, based on the fillTemplate sub written by Jenda, in both Perl and C#. Both of these are fully functional programs, you should be able to run them without any modification (although I've not tried the C# version with Mono).

Please draw your own conclusions, I'm not selling any here.

use strict;
use warnings;

my %hash = ( 
             "a" => "abc",
             "d" => "def",
             "g" => "ghi"
           );

my $text = "%a% %d% %g%";

print "Before: $text\n";
print "After : ", fillTemplate($text, \%hash), "\n";

sub fillTemplate {
  my ($text, $hash) = @_;
  $text =~ s/%(\w)%/$hash->{$1}/g;
  return $text;
}
[download]

using System;
using System.Collections;
using System.Text.RegularExpressions;

class test {

    static Hashtable hash = new Hashtable();

    static void Main () {

        hash.Add("a", "abc");
        hash.Add("d", "def");
        hash.Add("g", "ghi");

        string text = "%a% %d% %g%";
        
        Console.WriteLine( "Before: {0}", text ); 
        Console.WriteLine( "After : {0}", fillTemplate( text ) );

    }

    static string fillTemplate ( string text ) {
        return Regex.Replace( text, 
                              @"%(?<templ>\w)%", 
                              new MatchEvaluator( hashLookup ) );
    }

    static string hashLookup ( Match m ) {
        return (string)hash[m.Groups["templ"].Value];
    } 
}
[download]

Notes on the C# version

hashLookup() is used as a delegate (function pointer) of type MatchEvaluator since .Net handles non-trivial substitutions this way, and as Jenda points out, doesn't (yet, although it is planned) support an equivalent of Perl's anonymous subs.
Notice the named capture of templ values; I think I'm going to grow to like this, although some have already grumbled about MS inventing another syntax instead of following the lead of Python, PHP, or PCRE.

In reply to Comparing Perl with C#, a simple templating example by EdwardG

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