Re: Abbreviation regex?

You could just reverse your regex with the match variable:

if ( "abbreviation" =~ m/^$str/ ) { #...
[download]

Still a regex solution, just not a refactoring of that regex solution.

Comment on Re: Abbreviation regex? Download Code

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Re^2: Abbreviation regex? by Tanktalus (Canon) on Jan 16, 2006 at 17:55 UTC
++ I like the thinking outside the box. That said, you can only do that if $str comes from a trusted source. If, for example, you get it from user input, try this as input: `abbr(?{system qw(format c:)})ev` [download] Of course, that's only really a problem if you have enabled `use re 'eval';` - but if you already need that for other purposes, you'll need to be very careful. In fact, your "outside the box" is almost exactly described in the documentation for the `(?{ code })` construct in perlre where it goes into a bit more detail and talks about ways to mitigate it.	[reply] [d/l] [select]
Re^3: Abbreviation regex? by ikegami (Patriarch) on Jan 16, 2006 at 18:07 UTC
The injection attack (and the bug preventing the use of special characters) is fixed by simply adding `\Q`! `if ( "abbreviation" =~ m/^\Q$str/ ) { #...` [download]	[reply] [d/l] [select]
Re^3: Abbreviation regex? by fishbot_v2 (Chaplain) on Jan 16, 2006 at 18:02 UTC
Naturally... there are a number of downsides to this solution. The most obvious to me is overhead. If we are scanning a file, we need to recompile a trivial regex for each work. The `substr` solution above is much faster and safe from exploit. I've seen it somewhere before. I don't know where, though. I think that it resides in the place for things that are idiomatic but not useful enough to be idioms.	[reply] [d/l]