Re: Character class with negated "]"

[Hans-Bernhard Broeker]

On Mon, 9 Sep 2002, Hans Aberg wrote:

> How do I indicated a character class with a negated "]"?
> 
> I want to negate: * [ ]
> The problems is then that attempts like
>     [^*[]]+
> will not work, as the "]" will be interpreted as the character class
> closing bracket. 

For special cases like this, I seem to remember special
position-sensitivity built into most RE parsers.  Have you tried

        [^][*]+

At least with egrep, this does indeed work --- I haven't tested flex.

The idea is that ] will work if it's the first thing inside the [] pair,
where it cannot possibly mean the end of the class.  The '^' operator is
transparent for this, i.e. [ is still considered the first in this class.

-- 
Hans-Bernhard Broeker (address@hidden)
Even if all the snow were burnt, ashes would remain.