Re: Problem matching on [.]

[Nick Gammon <nick@...>]

On 16/05/2007, at 2:49 AM, Mark Edgar wrote:

> In fact not even the backslash is not special in classical (BRE and
> ERE) regexes when used in a bracket expression [].

I think it would be particularly helpful for the manual (and PiL) to  
spell out the reduced (or altered) set of magic characters inside a  
[ ... ] sequence.

There is an explicit list of magic characters outside the [ ... ]  
sequence, but not inside. For example, does [[] match a left bracket?  
(It appears it does).

A quick browse of the source would appear to indicate that inside the  
[ ... ] sequence only the following characters are special:

] -- to end the class, unless preceded by %
% -- to introduce a character class, or magic character
^ -- in the first position only, to negate the class
- -- between two characters, to specify a range

- Nick