[oak perl] Regular Expressions

[Belden Lyman]

On Wed, 2004-03-10 at 17:51, David Fetter wrote:
> On Wed, Mar 10, 2004 at 05:10:46PM -0800, Belden Lyman wrote:
>
> Belden, hats off for the ingenious use of regex, but...I don't quite
> get this approach.  Why try to cram it all into one regex?
> 

To prove to myself that it can all be done in one regex.

> Here's how I'd do a thing like this.  I suppose I lose obfuscation
> points, but it's easy to use, understand, modify, maintain, &c., and
> it's bumpin' fast.
> 

Sure, I wouldn't use anything like the above (err, the snipped?) in 
production code, exactly for the reasons you mentioned. It was an 
exercise, not much more.

> #!/usr/bin/perl -wl
> use strict;
> use warnings;
> use Getopt::Long;
> 
> my $file = '/usr/dict/words';
> my $length = 2;
> my $result = GetOptions(
>   "length=i" => \$length
> , "file=s"   => \$file
> );
> 
> open F, "<$file" or die "Couldn't open $file: $!\n";
> while(<F>) {
>     chomp;
      next unless /^\w+$/;           # ignore contractions
>     next unless length == $length; # Quickly removes most things we don't want.
>     next if $_ eq uc($_);          # No shouting.
>     next unless /[aeiouwy]/io;     # cwm is a word.
>                                    # more simple tests, if needed.
>     print;
> }
> close F;

Benchmarking certainly upholds your claim of bumpin' fast!

Belden