Squashed 'third_party/lisp/alexandria/' content from commit fc2a2f5c

git-subtree-dir: third_party/lisp/alexandria
git-subtree-split: fc2a2f5c34147bb4e3e4a350b04220de0263710f
This commit is contained in:
Vincent Ambo 2020-01-17 18:04:20 +00:00
commit 95aeb2ebae
29 changed files with 6252 additions and 0 deletions

14
features.lisp Normal file
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(in-package :alexandria)
(defun featurep (feature-expression)
"Returns T if the argument matches the state of the *FEATURES*
list and NIL if it does not. FEATURE-EXPRESSION can be any atom
or list acceptable to the reader macros #+ and #-."
(etypecase feature-expression
(symbol (not (null (member feature-expression *features*))))
(cons (check-type (first feature-expression) symbol)
(eswitch ((first feature-expression) :test 'string=)
(:and (every #'featurep (rest feature-expression)))
(:or (some #'featurep (rest feature-expression)))
(:not (assert (= 2 (length feature-expression)))
(not (featurep (second feature-expression))))))))