re-case

Arguments: string &rest clauses

string must be an expression that evaluates to a string. The clauses are then examined one by one, checking whether it matches string or not. clauses must be one of the following forms:

• (regexp bindings expr ...): if string matches regexp, (sub)matches are bound to the variables according to bindings, then expr ... are evaluated. See the documentation of re-lambda for information on the specifiction of regexp and bindings.
• (:test proc expr ...): proc must be an expression that evaluates to a procedure that takes single argument. proc is called with string, and if it returns a true value, evaluates expr ....
• (:testlet proc var expr ...): like :test above, but binds the result of proc to var while evaluating expr....
• (t expr ...): always match and evaluates expr .... This can be used to describe the fallback case.

If no clause match, nil is returned.

See also re-let and re-lambda.

Example

cl-user(4): (setq f
	      (re-lambda "([^ ]+) ([^ ]+) ([^ ]+)"
		  ((foo 1) (bar 2) (baz 3))
		(list foo bar baz)))
#<Interpreted Function (unnamed) @ #x71ed7892>
cl-user(5): (funcall f "foo the bar")
("foo" "the" "bar")
cl-user(6): (re-let "([^ ]+) ([^ ]+) ([^ ]+)"
		"foo the bar"
		((foo 1) (bar 2) (baz 3))
	      (list foo bar baz))
("foo" "the" "bar")
cl-user(7): 


cl-user(9): (re-case "foo the barmy"
	      ("foo a (.*)" ((it 1)) (list it))
	      ("foo the (.*)" ((it 1)) (list it))
	      (t :no-match))
("barmy")
cl-user(10): (re-case "foo a barmy"
	      ("foo a (.*)" ((it 1)) (list it))
	      ("foo the (.*)" ((it 1)) (list it))
	      (t :no-match))
("barmy")
cl-user(11): (re-case "foo xx barmy"
	      ("foo a (.*)" ((it 1)) (list it))
	      ("foo the (.*)" ((it 1)) (list it))
	      (t :no-match))
:no-match
cl-user(12): 

cl-user(30): (labels ((parse-date (input)
                        (re-case input
                          ("^(\\d{4})([-/])(\\d{1,2})\\2(\\d{1,2})$"
                           ((year 1) (month 3) (day 4))
                           (mapcar #'read-from-string (list year month day)))
                          ("^(\\d{1,2})([-/])(\\d{1,2})\\2(\\d{4})$"
                           ((year 4) (month 1) (day 3))
                           (mapcar #'read-from-string (list year month day)))
                          ("^(\\d{2})([-/])(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)\\2(\\d{4})$"
                           ((year 4) (month 3) (day 1))
                           (list
                            (read-from-string year)
                            (cdr
                             (assoc month
                                    '(("Jan" . 1) ("Feb" . 2) ("Mar" . 3)
                                      ("Apr" . 4) ("May" . 5) ("Jun" . 6)
                                      ("Jul" . 7) ("Aug" . 8) ("Sep" . 9)
                                      ("Oct" . 10) ("Nov" . 11) ("Dec" . 12))
                                    :test #'equal))
                            (read-from-string day))))))
               (list (parse-date "2004/7/21")
                     (parse-date "7-21-2004")
                     (parse-date "21-Jul-2004")))
((2004 7 21) (2004 7 21) (2004 7 21))
cl-user(31): 

The symbol naming this operator is also exported from the regexp package.

See The new regexp2 module in regexp.htm for further information on this macro and the regexp2 module.

Copyright (c) 1998-2022, Franz Inc. Lafayette, CA., USA. All rights reserved.
This page was not revised from the 10.0 page.
Created 2019.8.20.