Re: Bracket expressions with character ranges are slow

[Paolo Bonzini]

On 05/18/2011 07:44 PM, Seth David Schoen wrote:
> > >  You are correct that these cases (unlike ranges) can be optimized.
> Suppose grep had a preprocessor that converted any bracket
> expression containing elements of different byte sizes, whether
> [美国a] or a range not all of whose characters are a single byte,
> into a parenthesized alternation like (美|国|a).  Would this use
> more memory, constituting a space-for-time tradeoff?  If not, is
> there some other reason not to do this?

There's no justification but laziness. :)  We already optimized a large 
amount of character ranges---basically all that can be optimizaed except 
this one.

Paolo