Programming challenge

[Paul Seamons]

Here's my two minutes (plus two to clean it up and comment it):

#!/usr/bin/perl
my $a = "1 + 2:30 - 0:45:30.2 - 1:40.243";

$a =~ s{
  \b (\d+)                 # opening hour or minute
    : (\d+ (?:\.\d+)?)     # minute or second (decimals optional)
    (?:
       : (\d+ (?:\.\d+)?)  # seconds (if present) (decimals optional)
    )?
}{
    defined($3) # had seconds ?
        ? $3+60 * ($2+60 * $1)
        : $2+60 * $1
}xge;

print "($a)\n";

# prints
(1 + 150 - 2730.2 - 100.243)

That regex will also work in javascript as well.

Various assumptions were made that weren't described in the problem 
description.

Paul