Re: [Boost-users] [regex] Question about pattern

From: Boris (boriss_at_[hidden])
Date: 2008-02-27 04:19:03

On Tue, 26 Feb 2008 22:37:19 +0200, <office_at_[hidden]> wrote:

> [...]I tried starting with a pattern like (C++ syntax for strings)
>
> ^(?:(<|<=|>|>=|=|<>){1}((?:-|\\+)?[0-9]+(?:\\.[0-9]+|\\,[0-9]+)?))?(?:\\s*)(?:(\\[FG:(?:BLUE|RED|GREEN|BLACK|YELLOW|WHITE|CYAN|NONE)\\])|(\\[BG:(?:BLUE|RED|GREEN|BLACK|YELLOW|WHITE|CYAN)\\])|(\\[FG:(?:BBLUE|RED|GREEN|BLACK|YELLOW|WHITE|CYAN|NONE)\\])(?:\\s*)(\\[BG:(?:BLUE|RED|GREEN|BLACK|YELLOW|WHITE|CYAN)\\])){1}$
>
> But this does not allow the [fg:][bg:] terms to be interchanged and also
> when a new color or style will be added to the format class I have to
> change the pattern three times. I tried backward references with no
> success.

If regular expressions get as big as this and maybe even more complicated  
you might want to use Boost.Spirit instead. Boost.Spirit is not as easy to  
use as Boost.Regex but complicated expressions are broken down to  
something more easily understandable.

Boris