Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site sjuvax.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!sjuvax!jss From: jss@sjuvax.UUCP (J. Shapiro) Newsgroups: net.lang.c Subject: places where sets are useful Message-ID: <907@sjuvax.UUCP> Date: Tue, 26-Feb-85 02:14:27 EST Article-I.D.: sjuvax.907 Posted: Tue Feb 26 02:14:27 1985 Date-Received: Tue, 5-Mar-85 14:08:46 EST References: <10983@watmath.UUCP> <21000020@uiucuxc.UUCP> Organization: Saint Josephs Univ. Phila., Pa. Lines: 28 [Pacman's revenge...] It seems to me that in compiler writing, the case where one has multiple transitions on a single input character is an ideal case for sets. This is of course only an intermediate stage, so perhaps it does not justify a full blown set type. A better example is one of modal software, where one's modes are defined by a set of their names... For you pascalions: type mymodes = (insert, error, append, ...); var status = set of mymodes; begin ... if (status * [insert, append]) <> [] then begin.... ... end ... end. Is much more readable and therefore less likely to get mangled in software rewrites then is the exhaustive "if" phrasing. Jon Shapiro