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From: Kaz Kylheku <643-408-1753@kylheku.com>
Newsgroups: comp.lang.lisp
Subject: Re: Lisp history: IF, etc.
Date: Wed, 3 Apr 2024 20:57:48 -0000 (UTC)
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On 2024-04-03, Alan Bawden <alan@csail.mit.edu> wrote:
> Lisp doesn't really have statements _because_ McCarthy invented the
> conditional expression.  That's kind of the point.  Other programming
> languages at the time (e.g. FORTRAN and ALGOL) only had conditional
> statements.  McCarthy invented the conditional expression and thus
> created the first expression-only programming language.

However, conditional expressions ultimately come from math. E.g for
specifying a discontinuous function:

   f(x) = { x, if x >= 0
          { 0, if x < 0
 
If you think about it, it's actually kind of ignorant to invent a
programming language with imperative if statements, but in which where
the math conditional is missing.

> People sometimes sloppily say that "McCarthy invented the
> if-expression", by which they really mean just (1).  It is also true

That could be the origin of the misconception; someone is going to
take that sort of statement literally.

-- 
TXR Programming Language: http://nongnu.org/txr
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