Composed Regular Expressions - breaking a regex down into a readable form

Question

I was reading an article put together by Martin Fowler regarding Composed Regular Expressions. This is where you might take code such as this:

const string patt         


        

Answer 1

It is fairly easy to read if you can have extended syntax.

/^
  score   \s+ (\d+) \s+
  for     \s+ (\d+) \s+
  nights? \s+  at   \s+ (.*)
/x

I personally prefer Perl 6 style regex. I think they're easier to read.

rule pattern{
  score        $= [ <.digits>+ ]
  for          $=[ <.digits>+ ]
  night[s]? at $= [ .+ ]
}

After you perform a match against that rule $/ is associated with the matched text.

So something like this:

say "Hotel $/";
say $/.perl;

Would output something like this

Hotel name of hotel
{
  'hotel'  => 'name of hotel',
  'nights' => 5,
  'score'  => 8
}