Path: csiph.com!eternal-september.org!feeder.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: Paul Rubin <no.email@nospam.invalid>
Newsgroups: comp.lang.forth
Subject: Re: Implementing lisp in Forth. Chapter 4.
Date: Thu, 01 Sep 2016 19:49:12 -0700
Organization: A noiseless patient Spider
Lines: 38
Message-ID: <87twdznhhz.fsf@jester.gateway.pace.com>
References: <nq1ojd$rvh$1@cherry.spenarnc.xs4all.nl> <87bn0bplpm.fsf@jester.gateway.pace.com> <nq3ibl$2u3$1@cherry.spenarnc.xs4all.nl> <8737lkpr8n.fsf@jester.gateway.pace.com> <nq7rv3$lhl$1@cherry.spenarnc.xs4all.nl>
Mime-Version: 1.0
Content-Type: text/plain
Injection-Info: mx02.eternal-september.org; posting-host="7bfc8f5b1c0c0e2e29d3a5c3abe51644"; logging-data="5852"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX18NYp1qjW0eqLrEhb9/D+Qd"
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux)
Cancel-Lock: sha1:GqQl3TKM/8OgLDpfPkFMSHzX38U= sha1:2qHRhxtoaqubAHj9aAo6RM14ZqM=
Xref: csiph.com comp.lang.forth:50603

albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) writes:
>>a useful Lisp needs garbage collection.
> Don't get me wrong, I understand that. But some allocate/free pairs
> may be saved by using our usual stack approach

Yes probably true, that's just an optimization though, and it's easiest
to follow a straightforward approach first.  If there's a GC you might
as well use it, especially for stuff like the reader (Lisp terminology
for the thing that parses S-expressions).  Your Lisp isn't going to
spend much of its time doing that.

> Was gonna implement the parentheses as prefix/recognizer 

Would that also handle trailing parens (foo (bar (.... baz))) instead of
treating "baz)))" as a Forth word?

> There may be a fatal flaw. The lists of lvalues are not with links but
> are allocated arrays. 

I'm not sure what you mean by that: traditionally you'd use cons nodes
that each hold two values.

> a LISP vacobulary with compiling words
> ( prefix

I wouldn't try to use the Forth text interpreter directly as a Lisp
reader.  You start wanting read macros written in Lisp, etc.  Assuming
the target machine is a PC or comparable, I wouldn't worry about the
efficiency of the reader.  I doubt you're planning to run megabytes of
Lisp code.

> This saturday Willem Ouwerker is going to present a two and a
> sex legged robot at a combined meeting of the Robot and AI
> user groups. I'll meet an AI Lisp expert there.

Nice.  It occurs to me given your interest in Euler problems, that your
Lisp should also have bignums.