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From: brian@granite.jpl.nasa.gov (Brian of ASTD-CP)
Newsgroups: comp.lang.lisp
Subject: Dumb Common Lisp question
Summary: CLtL2: why exists #' ?
Message-ID: <4204@jato.Jpl.Nasa.Gov>
Date: 28 Jun 90 23:18:12 GMT
Sender: news@jato.Jpl.Nasa.Gov
Reply-To: brian@granite.Jpl.Nasa.Gov (Brian of ASTD-CP)
Distribution: usa
Organization: Jet Propulsion Laboratory, Pasadena, CA
Lines: 29

I spent last weekend reading Steele's CLtL2 (Common Lisp the
Language, second edition).  What a tour de force!  I think I'll
be dizzy for at least another week.

I have one pressing question about CL.  What is the rationale
behind the (function ...) or #' construct?  It seems in some
places you need to say #'foo, say in an apply, and in other
places you just say foo, as in (foo 1 2 3).  Thus it seems to
be the programmer's job to remember when "the function itself"
and "the name of the function" are needed by CL.

What I mean is, why is this in the language?  The book is
very thorough on the _rules_for_using_ #', so I don't need your
help with that.  I can't find any rationale in the book,
though.  Does it allow the compiler to improve efficiency?  Is
it there for historical reasons?  What gives?

I'm most familiar with Scheme/T, where this kind of thing is
not necessary.  All symbols are evaluated the same way in
application expressions (func arg arg), and the value of func
is a function.  Treating a function as just another data type
like integer or string seems very neat and clean.  There must
be some reason it's not done this way in CL.


 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
 . . Brian Beckman . . . . . . . . . . brian@granite.jpl.nasa.gov. . . .
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