Re: Precedence values for Reverse Polish

anton@mips.complang.tuwien.ac.at (Anton Ertl)
18 Nov 1999 02:46:13 -0500

          From comp.compilers

Related articles
[3 earlier articles]
Re: Precedence values for Reverse Polish ppaatt@aol.com (1999-10-31)
Re: Precedence values for Reverse Polish nerd@freeuk.com (Nerd) (1999-10-31)
Re: Precedence values for Reverse Polish anton@mips.complang.tuwien.ac.at (1999-11-02)
Re: Precedence values for Reverse Polish ppaatt@aol.com (1999-11-02)
Re: Precedence values for Reverse Polish anton@mips.complang.tuwien.ac.at (1999-11-03)
Re: Precedence values for Reverse Polish ppaatt@aol.com (1999-11-05)
Re: Precedence values for Reverse Polish anton@mips.complang.tuwien.ac.at (1999-11-18)
Re: Precedence values for Reverse Polish world!bobduff@uunet.uu.net (Robert A Duff) (1999-11-25)
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From: anton@mips.complang.tuwien.ac.at (Anton Ertl)
Newsgroups: comp.compilers
Date: 18 Nov 1999 02:46:13 -0500
Organization: Institut fuer Computersprachen, Technische Universitaet Wien
References: 99-11-026 99-11-034
Keywords: parse, code, comment

  ppaatt@aol.com (PPAATT) writes:
>Once running, given the ability to construct anonymous fragments of
>code, there is no run-time use for the quote special form?
>
>Except in engines that convert text to executable - like, say, Lisp
>source text to executable.
>
>I don't feel like I'm saying this very well - not sure what to do
>about it - is my question clear?


Not really.


The difference between normal functions and special forms is that
normal functions always evaluate all arguments before the call. This
is a difference in semantics, not just syntax. And you need at least
one special form so you can pass literals to functions; at the very
least you need them for literal atoms; hmm, if you changed Lisp to
evaluate atoms to themselves, and have a function "lookup" for looking
up variables etc., you might get away without quote; but the language
would be quite cumbersome to use.


- anton
--
M. Anton Ertl Some things have to be seen to be believed
anton@mips.complang.tuwien.ac.at Most things have to be believed to be seen
http://www.complang.tuwien.ac.at/anton/home.html
[Bliss treated all names as quoted and you had to defereference everything
explicitly. It was a major pain in the neck. -John]


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