cl-ppcre is a portable CL#

Sun, 24 Aug 2003 07:16:35 +0000

cl-ppcre is a portable CL package providing perl-compatible regexps. There are two things I'd like to say about it on the basis of ten minutes use

(asdf-install:install "/home/dan/cl-ppcre.tgz") Install where? 1) System-wide install: System in #P"/usr/local/lib/sbcl/site-systems/" Files in #P"/usr/local/lib/sbcl/site/" 2) Personal installation: System in #P"/home/dan/.sbcl/systems/" Files in #P"/home/dan/.sbcl/site/" --> 2 Installing /home/dan/cl-ppcre.tgz in #P"/home/dan/.sbcl/site/",#P"/home/dan/.sbcl/systems/" cl-ppcre-0.5.7/ [ ... and so it goes ]

Although billed as perl-compatible, that doesn't mean you have to use the Perl syntax: you can also write regexes as trees. For example

(defparameter postcode-p
  (let ((a '(:CHAR-CLASS (:RANGE #\a #\z)))
	(n :digit-class)
	(s '(:GREEDY-REPETITION 0 NIL :WHITESPACE-CHAR-CLASS)))
    (cl-ppcre:create-scanner
     `(:alternation
       (:sequence ,a ,n       ,s  ,N ,A ,A)
       (:sequence ,A ,N ,N    ,s  ,N ,A ,A)
       (:sequence ,A ,A ,N    ,s  ,N ,A ,A)
       (:sequence ,A ,A ,N ,N ,s  ,N ,A ,A)
       (:sequence ,A ,N ,A    ,s  ,N ,A ,A)
       (:sequence ,A ,A ,N ,A ,s  ,N ,A ,A)))))
 (cl-ppcre:scan postcode-p "w1y 1ha")
0
7
()
()

That's a regex for UK postcodes (actually, not quite. I should add the special case for GIR 0AA, which apparently is Alliance & Leicester Girobank Plc in Bootle). Isn't it just much easier to see what it does as a tree?