Path: ...!weretis.net!feeder8.news.weretis.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Lawrence D'Oliveiro Newsgroups: comp.lang.lisp Subject: Re: Lisp history: IF, etc. Date: Thu, 4 Apr 2024 00:11:17 -0000 (UTC) Organization: A noiseless patient Spider Lines: 15 Message-ID: References: <20240329084454.0000090f@gmail.com> <20240329101248.556@kylheku.com> <20240329104716.777@kylheku.com> <20240330112105.553@kylheku.com> <87r0fp8lab.fsf@tudado.org> <87wmpg7gpg.fsf@tudado.org> <20240402084057.881@kylheku.com> <86h6gjpq3i.fsf_-_@williamsburg.bawden.org> <86cyr6pb2l.fsf@williamsburg.bawden.org> <875xwy412p.fsf@nightsong.com> <868r1up0wk.fsf@williamsburg.bawden.org> <871q7m3wrj.fsf@nightsong.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Injection-Date: Thu, 04 Apr 2024 00:11:17 +0200 (CEST) Injection-Info: dont-email.me; posting-host="b2ebab76618f2906d24b8f2b6b05668a"; logging-data="250895"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/Vf3CewSEe5/IOn4IngE4b" User-Agent: Pan/0.155 (Kherson; fc5a80b8) Cancel-Lock: sha1:tA7K5tkASSLSv100WpfQvaomR5Y= Bytes: 2147 On Wed, 03 Apr 2024 15:29:52 -0700, Paul Rubin wrote: > I think lazy evaluation is not needed since the > input to the Church boolean (I hope I have the jargon right) is two > lambda abstractions. The boolean selects one of them, and the result is > applied to whatever the next thing is. I use this in Python, to try to avoid that abortion that is the Python conditional expression. Instead of, say, a = x / y if y != 0 else 0 I would do a = (lambda : 0, lambda : x / y)[y != 0]()