Re: [PATCH] Exclude optimization

[Sergey Poznyakoff]

Hi Bruno,

> 'is_fnmatch_pattern' is probably a misnomer, because its argument is
> by definition already an fnmatch pattern. What the function is testing is
> whether it contains wildcard characters

Yes, indeed.

> Btw, this function does not handle multiple adjacent backslashes correctly,
> i.e. patterns such as 'ab\\[cd]'.
> 
> Also, I'm surprised that this function does not take an 'options' argument.
> For example, the string 'ab\[cd\]' is constant if FNM_NOESCAPE is off, but
> non-constant if FNM_NOESCAPE is on.

Good catch. I'll fix this.

> I would like to see some unit tests committed to this module before the
> big optimization.

OK, I'll write some.

> Thinking more into the future, there are now multiple optimizations of
> regex / fnmatch from various sides. (Recall that fnmatch patterns can
> be transformed into regular expressions.)

By the way, I am also experimenting with the idea of re-implementing
the exclude module using DFA, i.e. regarding the entire exclude list
as a set of regular language definitions and creating a DFA for each
of them (it is a *set* of definitions, because its parts can have
different EXCLUDE_* flags, so they should be processed differently).
This may constitute a significant speed-up. 

Regards,
Sergey