regexp-opt

regexp-opt is an autoloaded compiled Lisp function in `regexp-opt.el'.

(regexp-opt STRINGS &optional PAREN)

Return a regexp to match a string in the list STRINGS.
Each string should be unique in STRINGS and should not contain any regexps,
quoted or not. If optional PAREN is non-nil, ensure that the returned regexp
is enclosed by at least one regexp grouping construct.
The returned regexp is typically more efficient than the equivalent regexp:

(let ((open (if PAREN "\\(" "")) (close (if PAREN "\\)" "")))
(concat open (mapconcat 'regexp-quote STRINGS "\\|") close))

If PAREN is `words', then the resulting regexp is additionally surrounded
by \< and \>.
If PAREN is `symbols', then the resulting regexp is additionally surrounded
by \_< and \_>.