#!/usr/bin/perl -W

# Copyright Jacob Filipp, 2003
# This program is provided as is, you are free to use
# it in any way as long as the copyright notice is
# in the code
 
# Yes dear monks, Quick-And-Dirty-Operating-System (DOS)
# is still used. Here is a tiny shell wrapper in Perl,
# to implement all the wonderful features that DOS lacks
# ,like command aliasing. Although this tiny script is
# meagre compared to your mathematical-script prowess
# it is very flexible and someone might actually like
# to use it ( from sheer curiosity, of course ).

# The only fancy trick it has is the ability to launch
# your browser when a URL is typed ( the first case in
# the dispatch table. Interactive progs are run in a
# separate window.

use Strict;     # just for you monks, I never use it

$SIG{ CHLD } = sub{ wait() };

$browser_path  = 'C:\Program Files\Internet Explorer\iexplore';
$prompt   = sub{ 'Sh-wrap>' };	# can be a routine...
@kids = ();			# forked processes

# dispatch table with regexes, used to execute commands
# based on a shell command passed to it as an argument

%dispatch = (

'^(http://)?\S+\.(\w){3}.*$'        =>sub{
	my $kpid = fork();
	if( $kpid == 0 ){ exec("\"$browser_path\" $_[0]") and exit}
	else { push( @kids, $kpid ); sleep 1 }
# sleep needed to make sure that child acts first
	},

'^cd\s'		=> sub
	{ $_[0] =~ s!^cd\s!!; chdir($_[0]) },

'^(exit|quit)$'	=> sub{ kill( 9, @kids); exit },

'^(ftp|telnet|edit|debug).*'	=> sub { `start $_[0]` }
# interactive progs in new window
# will barf when running ftpd, telnetter, editors, debuggame etc...
);

WH: while(1)
{

print $prompt->();
my $line = <>;
chomp $line;

foreach $regex ( keys %dispatch )
 {
   if( $line =~ m!$regex! )
   { $dispatch{ $regex }->($line); next WH }
   # permit only one match
 }

print `$line`;

}