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Re: Implementing lisp in Forth. Chapter 4.

From Paul Rubin <no.email@nospam.invalid>
Newsgroups comp.lang.forth
Subject Re: Implementing lisp in Forth. Chapter 4.
Date 2016-08-31 14:23 -0700
Organization A noiseless patient Spider
Message-ID <8737lkpr8n.fsf@jester.gateway.pace.com> (permalink)
References <nq1ojd$rvh$1@cherry.spenarnc.xs4all.nl> <87bn0bplpm.fsf@jester.gateway.pace.com> <nq3ibl$2u3$1@cherry.spenarnc.xs4all.nl>

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albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) writes:
> Native Types ...
> Which of those are in the 1000 lines toy lisps that is written
> in Forth or c anyway?

That is all pretty standard, though 1kloc may be a bit light.  You could
look at the early versions of SIOD (Scheme In One Day) by George
Carrette, or more recently Tinyscheme (used in GIMP etc).

> Thanks for the comment. I hope you will look at the next chapters too.
> The next step is parsing. It generates data structures. It will require
> major design decisions how to do that in Forth. My hope is that by
> allocating part of those structures (objects) on the data stack, much
> of the freeing will be swift and painless.

That's not realistic, a useful Lisp needs garbage collection.  

I'm not impressed by that book's approach to parsing either (using fancy
parser combinators written in C).  Lisp is syntactically very simple,
almost like Forth.  Forth just uses non-whitespace tokens delimited by
whitespace, giving a linear structure.  Lisp adds parentheses to denote
lists of conses, so you get tree structure.  

I haven't completely thought this through so maybe there is a fatal
flaw, but if I wanted to write a Lisp in Forth, I'd consider this
approach:

- write the reader and printer in Lisp, using an existing Lisp for
  bootstrapping and testing.

- Write the usual Lisp primitives (CONS, CAR, CDR) etc. as Forth words
  that call alloc to get storage for new conses.

- Have the reader intern new symbols into the Forth dictionary (might
  need carnal knowledge or hacking of your Forth) putting DEFER
  around everything, since Lisp uses late binding.  Self-evaluating
  symbols would call a Forth word that takes an address arg.
  (define (f x) ...) would make an IS to actually bind the "f" symbol
  (earlier interned as a deferred) to a code address.  

- Use Anton's Boehm-style garbage collector instead of attempting
  precise GC

- Don't have an evaluator but instead have a compiler written in Lisp,
  that tree-walks Lisp functions and emits Forth code, either as
  threaded code to be run by your Forth's address interpreter, or as
  Forth source code that you'd pass through a text interpreter.  (It
  wouldn't look like human-written code because of all the deferred
  symbols, the use of special Lisp operators like "Lisp+" instead of "+"
  that would have to dispatch on types, etc.  But still, now your Lisp
  code can call Forth words and vice versa, maybe using a small
  FFI to convert between tagged and untagged values.

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Implementing lisp in Forth. Chapter 4. albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-08-29 18:41 +0200
  Re: Implementing lisp in Forth. Chapter 4. Paul Rubin <no.email@nospam.invalid> - 2016-08-29 09:39 -0700
    Re: Implementing lisp in Forth. Chapter 4. albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-08-30 10:49 +0200
  Re: Implementing lisp in Forth. Chapter 4. Paul Rubin <no.email@nospam.invalid> - 2016-08-29 09:46 -0700
    Re: Implementing lisp in Forth. Chapter 4. albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-08-30 11:07 +0200
      Re: Implementing lisp in Forth. Chapter 4. Rod Pemberton <NoHaveNotOne@zxdehrnyya.cam> - 2016-08-30 08:00 -0400
        Re: Implementing lisp in Forth. Chapter 4. albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-02 12:34 +0200
      Re: Implementing lisp in Forth. Chapter 4. Paul Rubin <no.email@nospam.invalid> - 2016-08-31 14:23 -0700
        Re: Implementing lisp in Forth. Chapter 4. albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-01 02:15 +0200
          Re: Implementing lisp in Forth. Chapter 4. Paul Rubin <no.email@nospam.invalid> - 2016-09-01 19:49 -0700
            Re: Implementing lisp in Forth. Chapter 4. albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-02 11:49 +0200
              Re: Implementing lisp in Forth. Chapter 4. Paul Rubin <no.email@nospam.invalid> - 2016-09-04 11:28 -0700
                Re: Implementing lisp in Forth. Chapter 4. albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-05 03:31 +0200
                Re: Implementing lisp in Forth. Chapter 4. Paul Rubin <no.email@nospam.invalid> - 2016-09-04 21:03 -0700
                Re: Implementing lisp in Forth. Chapter 4. Spiros Bousbouras <spibou@gmail.com> - 2016-09-05 07:47 +0000
                Re: Implementing lisp in Forth. Chapter 4. albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-05 12:05 +0200
                Re: Implementing lisp in Forth. Chapter 4. Paul Rubin <no.email@nospam.invalid> - 2016-09-05 12:04 -0700
                Re: Implementing lisp in Forth. Chapter 4. albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-06 11:48 +0200
                Re: Implementing lisp in Forth. Chapter 4. Spiros Bousbouras <spibou@gmail.com> - 2016-09-06 15:32 +0000
                Re: Implementing lisp in Forth. Chapter 4. albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-06 21:27 +0200
                Re: Implementing lisp in Forth. Chapter 4. anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-06 19:50 +0000
                Re: Implementing lisp in Forth. Chapter 4. Stefan Monnier <monnier@iro.umontreal.ca> - 2016-09-08 12:15 -0400
                Re: Implementing lisp in Forth. Chapter 4. albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-08 20:09 +0200
                Re: Implementing lisp in Forth. Chapter 4. Paul Rubin <no.email@nospam.invalid> - 2016-09-08 12:34 -0700
                Re: Implementing lisp in Forth. Chapter 4. anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-12 10:17 +0000
                Re: Implementing lisp in Forth. Chapter 4. Stefan Monnier <monnier@iro.umontreal.ca> - 2016-09-12 11:50 -0400
                Re: Implementing lisp in Forth. Chapter 4. anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-12 16:48 +0000
                Re: Implementing lisp in Forth. Chapter 4. Stefan Monnier <monnier@iro.umontreal.ca> - 2016-09-12 13:41 -0400
                Re: Implementing lisp in Forth. Chapter 4. Paul Rubin <no.email@nospam.invalid> - 2016-09-06 22:03 -0700
                Re: Implementing lisp in Forth. Chapter 4. George Neuner <gneuner2@comcast.net> - 2016-09-08 16:50 -0400
                Re: Implementing lisp in Forth. Chapter 4. Paul Rubin <no.email@nospam.invalid> - 2016-09-08 16:34 -0700
                Re: Implementing lisp in Forth. Chapter 4. George Neuner <gneuner2@comcast.net> - 2016-09-09 00:12 -0400
                Re: Implementing lisp in Forth. Chapter 4. Paul Rubin <no.email@nospam.invalid> - 2016-09-08 22:22 -0700
                Re: Implementing lisp in Forth. Chapter 4. Lars Brinkhoff <lars.spam@nocrew.org> - 2016-09-27 08:51 +0200
                Re: Implementing lisp in Forth. Chapter 4. Paul Rubin <no.email@nospam.invalid> - 2016-09-27 00:47 -0700
                Re: Implementing lisp in Forth. Chapter 4. Spiros Bousbouras <spibou@gmail.com> - 2016-09-06 13:18 +0000
                Re: Implementing lisp in Forth. Chapter 4. "WJ" <w_a_x_man@yahoo.com> - 2016-09-06 20:52 +0000
                Re: Implementing lisp in Forth. Chapter 4. albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-11-02 19:15 +0100
                Re: Implementing lisp in Forth. Chapter 4. Lars Brinkhoff <lars.spam@nocrew.org> - 2016-09-09 10:05 +0200
                Re: Implementing lisp in Forth. Chapter 4. anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-12 10:11 +0000
                Re: Implementing lisp in Forth. Chapter 4. Lars Brinkhoff <lars.spam@nocrew.org> - 2016-09-12 13:15 +0200
                Re: Implementing lisp in Forth. Chapter 4. anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-12 17:25 +0000
                Re: Implementing lisp in Forth. Chapter 4. albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-09 16:19 +0200
                Re: Implementing lisp in Forth. Chapter 4. Paul Rubin <no.email@nospam.invalid> - 2016-09-09 10:55 -0700
                Re: Implementing lisp in Forth. Chapter 4. albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-09 21:39 +0200
                Re: Implementing lisp in Forth. Chapter 4. Paul Rubin <no.email@nospam.invalid> - 2016-09-09 13:06 -0700
                Re: Implementing lisp in Forth. Chapter 4. franck.bensusan@gmail.com - 2016-09-10 07:23 -0700
                Re: Implementing lisp in Forth. Chapter 4. Paul Rubin <no.email@nospam.invalid> - 2016-09-11 01:28 -0700
                Re: Implementing lisp in Forth. Chapter 4. Spiros Bousbouras <spibou@gmail.com> - 2016-09-13 21:37 +0000
                Re: Implementing lisp in Forth. Chapter 4. albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-14 09:55 +0200
                Re: Implementing lisp in Forth. Chapter 4. franck.bensusan@gmail.com - 2016-09-14 01:04 -0700
                Re: Implementing lisp in Forth. Chapter 4. Paul Rubin <no.email@nospam.invalid> - 2016-09-13 14:40 -0700
                Re: Implementing lisp in Forth. Chapter 4. franck.bensusan@gmail.com - 2016-09-14 03:37 -0700
                Re: Implementing lisp in Forth. Chapter 4. lawrencedo99@gmail.com - 2016-09-10 01:17 -0700
                Re: Implementing lisp in Forth. Chapter 4. Paul Rubin <no.email@nospam.invalid> - 2016-09-10 12:01 -0700
                Re: Implementing lisp in Forth. Chapter 4. lawrencedo99@gmail.com - 2016-09-10 21:57 -0700
                Re: Implementing lisp in Forth. Chapter 4. Paul Rubin <no.email@nospam.invalid> - 2016-09-10 22:12 -0700
                Re: Implementing lisp in Forth. Chapter 4. lawrencedo99@gmail.com - 2016-09-10 23:30 -0700
                Re: Implementing lisp in Forth. Chapter 4. Paul Rubin <no.email@nospam.invalid> - 2016-09-10 23:48 -0700
                Re: Implementing lisp in Forth. Chapter 4. Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-09-11 02:59 -0500
                Re: Implementing lisp in Forth. Chapter 4. Paul Rubin <no.email@nospam.invalid> - 2016-09-11 01:16 -0700
                Re: Implementing lisp in Forth. Chapter 4. lawrencedo99@gmail.com - 2016-09-11 19:02 -0700
                Re: Implementing lisp in Forth. Chapter 4. lawrencedo99@gmail.com - 2016-09-11 19:00 -0700
                Re: Implementing lisp in Forth. Chapter 4. Paul Rubin <no.email@nospam.invalid> - 2016-09-10 12:08 -0700
                Re: Implementing lisp in Forth. Chapter 4. anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-12 09:43 +0000
                Re: Implementing lisp in Forth. Chapter 4. albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-12 13:42 +0200
                Re: Implementing lisp in Forth. Chapter 4. anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-12 17:26 +0000
                Re: Implementing lisp in Forth. Chapter 4. albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-12 20:56 +0200
                Re: Implementing lisp in Forth. Chapter 4. Paul Rubin <no.email@nospam.invalid> - 2016-09-12 13:08 -0700
                Re: Implementing lisp in Forth. Chapter 4. anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-09-14 07:38 +0000
    Re: Implementing lisp in Forth. Chapter 4. Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2016-09-30 07:48 +0100
      Re: Implementing lisp in Forth. Chapter 4. albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-30 11:22 +0200
      Re: Implementing lisp in Forth. Chapter 4. Paul Rubin <no.email@nospam.invalid> - 2016-09-30 18:36 -0700
        Re: Implementing lisp in Forth. Chapter 4. albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-10-01 11:19 +0200
          Re: Implementing lisp in Forth. Chapter 4. luser droog <mijoryx@yahoo.com> - 2016-10-01 19:34 -0700
  Implementing lisp in Forth. Garbage collection. albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-06 12:30 +0200
    Re: Implementing lisp in Forth. Garbage collection. Spiros Bousbouras <spibou@gmail.com> - 2016-09-06 15:34 +0000
      Re: Implementing lisp in Forth. Garbage collection. albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-06 21:12 +0200
    Re: Implementing lisp in Forth. Garbage collection. Paul Rubin <no.email@nospam.invalid> - 2016-09-06 14:52 -0700
      Re: Implementing lisp in Forth. Garbage collection. albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-09-07 01:50 +0200
        Re: Implementing lisp in Forth. Garbage collection. Paul Rubin <no.email@nospam.invalid> - 2016-09-06 17:49 -0700
  Re: Implementing lisp in Forth. Chapter 4. luser droog <mijoryx@yahoo.com> - 2016-10-21 17:02 -0700
    Re: Implementing lisp in Forth. Chapter 4. albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2016-10-22 02:43 +0200

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