/usr/share/common-lisp/source/alexandria/features.lisp is in cl-alexandria 20170630-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | (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))))))))
|