Newsgroups: comp.lang.scheme Path: utzoo!sq!dak From: dak@sq.sq.com (David A Keldsen) Subject: Re: why is quasiquote necessary? Message-ID: <1990May31.214540.21763@sq.sq.com> Organization: SoftQuad Inc. References: Distribution: comp.lang.scheme Date: Thu, 31 May 90 21:45:40 GMT alms@cambridge.apple.com (Andrew L. M. Shalit) writes: >It occurred to me today that Scheme doesn't really need a quasiquote >special form. Instead, quote could have just been extended to handle >unquote and unquote-splicing. >I can only think of two reasons for having both quote and quasiquote: > 1) historical accident, because of the way the quasiquote special > form was derived from a reader macro. > 2) program readability. Some would argue that a large quoted piece of > program text with a little bitty comma in the middle might be prone > to misinterpretation (by humans). I respectfully disagree [that Scheme doesn't need the quote-quasiquote distinction]. This (IMHO) is one of those places where full generality is *not* a good thing. In particular, both human and machine readers of quasiquoted phrases must scan the *entire* phrase, looking for unquotes...which is an efficiency loss. Quote allows one to say, "OK, stop looking, the rest is unevaluated." It's a common enough case that it is worth the difference in notation. > -andrew -- // David A. 'Dak' Keldsen: dak@sq.com or utai[.toronto.edu]!sq!dak // "I have heard the mermaids singing, each to each." -- T.S.Eliot