#!/usr/bin/perl

# Josh Hursey
# April 3, 2003

use strict;

my $argc = scalar(@ARGV);
my $expr;

for(my $i=0; $i < $argc; ++$i){
    $expr .= $ARGV[$i] . " ";
}
chop($expr);
print "Your Expression:<$expr>\n";
print "----------------\n";

my $example = "hot cross buns";
print "Example from Programming Perl Book:\n";
print "\t$example\n";
if($example =~ /cross/){
    print "Matched: <$`> $& <$'>\n";
    print "Left:   <$`>\n";
    print "Match:  <$&>\n";
    print "Right:  <$'>\n";
}

print "----------\n";
print "Determine if x is in your expression\n";
if($expr =~ /x/){
    print "\tYep I found one!\n";
}
else {
    print "\tNope, No x's in this one!\n";
}

print "----------\n";
print "Determine if x or y is in your expression\n";
if($expr =~ /[xy]/){
    print "\tYep I found one!\n";
}
else {
    print "\tNope, No x's or y's in this one!\n";
}

print "----------\n";
print "Does it start with x followed by at least one y?\n";
if($expr =~ /^xy+/){ 
    print "\tYep!\n";}
else { print "\tNope!\n"; }

print "----------\n";
print "It is a digit or series of digits then\n";
if($expr =~ /^[0-9]+$/){ 
    print "\tYep!\n";}
else { print "\tNope!\n"; }

print "----------\n";
print "Is it just one and only one word thus\n";
if($expr =~ /^(thus)$/){ 
    print "\tYep!\n";}
else { print "\tNope!\n"; }

print "----------\n";
print "Take this expression:\n";
my $story = "Once upon a time there was a little rabbit...";
print "\t<$story>\n";
print "Replace all of the 'little's with 'BIG's\n";
$story =~ s/little/BIG/;
print "Now heres a story:\n";
print "\t<$story>\n";

print "----------\n";
print "Hope this helps a bit, take a look on the web, \n";
print "and don't be afraid to experament in little scripts.\n";
print "That is the best way to learn Regular Expressions.\n";
print "----------\n";

exit;