EXT:FCASE
This macro allows specifying the test for CASE
, e.g.,
(fcase string= (subseq foo 0 (position #\Space foo)) ("first" 1) (("second" "two") 2) (("true" "yes") t) (otherwise nil))
is the same as
(let ((var (subseq foo 0 (position #\Space foo)))) (cond ((string= var "first") 1) ((or (string= var "second") (string= var "two")) 2) ((or (string= var "true") (string= var "yes")) t) (t nil)))
If you use a built-in HASH-TABLE
test (see Section 18.4, “Function HASH-TABLE-TEST
”)
as the test (e.g., EQUAL
instead of STRING=
above, but not a test
defined using EXT:DEFINE-HASH-TABLE-TEST
), the compiler will be able to optimize the
EXT:FCASE
form better than the corresponding COND
form.
These notes document CLISP version 2.49 | Last modified: 2010-07-07 |