Re: Guile regular expressions are too greedy [Solved]

[Chris Dennis <cgdennis@btinternet.com>]

Peter Brett wrote:
> Chris Dennis <cgdennis@btinternet.com> writes:
> 
>> Hello Guile People
>>
>> Is there a way to make Guile regular expressions less greedy?  I
>> understand that POSIX doesn't define non-greedy modifiers.
>>
>> Specifically, I'm trying to parse font names such as
>>
>>     Arial 12
>>     Arial Bold Italic 14
>>     Nimbus Sans L Bold Italic Condensed 11
>>
>> so that I can construct CSS styles from them.
>>
>> I've tried the following, but the first (.*) gobbles up everything
>> before the size because the other elements are optional:
>>
>> (define s (string-match "(.*)( +(bold|semi-bold|regular|light))?(
>> +(italic|oblique))?( +(condensed))? +([0-9]+)" "nimbus sans l bold
>> italic condensed 11"))
>>
>>
>> Are there other ways of doing this?
>>
> 
> Does this work for you?
> 
> (define (parsefont str)
>   (let ((match (string-match "( +(bold|semi-bold|regular|light))?( +(italic|oblique))?( +(condensed))? +([0-9]+)" str)))
>     (cons (match:prefix match)
>           (map (lambda (n) (match:substring match n)) '(2 4 6 7)))))
> 
> (parsefont "nimbus sans l bold italic condensed 11")
> 
> ==> ("nimbus sans l" "bold" "italic" "condensed" "11")
> 
> HTH,
> 
>                                      Peter
> 

Brilliant!  I was just about to give up on regular expressions and write 
some tedious string-manipulation code.  That works perfectly.  Thank you 
very much.

(That code will now become part of GnuCash).

cheers

Chris

-- 
Chris Dennis                                  cgdennis@btinternet.com
Fordingbridge, Hampshire, UK