46 lines
1.7 KiB
Plaintext
46 lines
1.7 KiB
Plaintext
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Subject: on bootstrapping: introducing Mes
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Date: Sun, 19 Jun 2016 13:08:02 +0200
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Hi,
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I have a minimal LISP-1.5-resembling interpreter in C that now can
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also interpret itself
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https://gitlab.com/janneke/mes
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It was inspired by the seemingly often ignored bootstrapping question
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made so painfully visible by GuixSD and by OriansJ with their self
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hosting hex assembler project.
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As a next step after a hex assembler I was thinking of getting Scheme up
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and running and use that to create a tiny C compiler, probably using
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PEG. For that I think we need define-syntax, which I had a peek at and
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still scares the all-sorts-of-things out of me :-)
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I searched for minimal Lisp/Scheme to get that going and found an
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article called the Maxwell Equations of Software 1) with a pointer to
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the 1962 LISP 1.5 paper by John McCarthy 2).
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First I `implemented' Mes/LISP-1.5: the bottom half of page 13 and the
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necessary helper procedures defined on pages 8-12 using Guile, removing
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all but the primitives needed to run LISP-1.5/Mes (I think): car, cdr,
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cond, cons, define, eq?, '()/nil, null?, pair? and quote. I cheated
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with read, and with display and newline for debugging.
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Then I translated the program into C and got rid of read by using
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getchar/ungetchar.
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It's been great fun and now I'm kind of stuck a bit at the point of
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implementing macros. I have a simplistic version in C but want to
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remove that again --I like the idea of having the absolute minimal LISP
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interpreter in C-- and only introduce macros after having bootstrapped
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into the LISP/Mes domain.
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Greetings,
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Jan
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1) http://www.michaelnielsen.org/ddi/lisp-as-the-maxwells-equations-of-software/
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2)
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http://www.softwarepreservation.org/projects/LISP/book/LISP%201.5%20Programmers%20Manual.pdf
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