On Fri, 6 Sep 2002, Mr. Nobody wrote:
> While Apocolypse 5 raises some good points about problems with the old regex
> syntax, its new syntax is actually worse than in perl 5. Most regexes, such
> as this one to match a C float
>
> /^([+-]?)(?=\d|\.\d)\d*(\.\d*)?([Ee]([+-]?\d+))?$/
>
> would actually become longer:
>
> /^(<[+-]>?)<before \d|\.\d>\d*(\.\d*)?(<[Ee]>(<[+-]>?\d+))?$/
We've seen this a lot. Many patterns do become longer. But saying that's
a flaw is erroneous. Much of the point of A5 was to make patterns
*clearer*, not shorter.
Your example of the C float in both syntaxes is exactly what we're trying
to get away from. Patterns will become readable code, not just line
noise.
/ <[+-]>? [ # Mantissa
\d* \. \d+
|
\d+ \.?
]
<[Ee]> <[+-]>? \d+ # Exponent
/
That's not as good as it *could* be, but it's better than both of those
above. And it's better than the equivilent Perl5 /x pattern.
> Therefore I propose a few minor changes:
>
> character class: [...]
> non-captured group: {...}
> closure: <{...}>
> lookahead assertion: <b ...>
> lookbehind assertion: <a ...>
>
> This would bring the aforementioned regex back down to perl 5 size, and many
> would become even shorter than in perl 5.
So is your career Golf? Because a lot of people program in Java, even
though it takes 7.2e33 lines what would take Perl 13. And a lot of people
prefer Java (but not us).
Size isn't everything; it's how you use it ;)
Luke
