Subject: Re: is Lisp used in text parsing and processing tasks?
From: (Rob Warnock)
Date: Thu, 14 Nov 2002 23:07:57 -0600
Newsgroups: comp.lang.lisp
Message-ID: <>
Petter Gustad  <> wrote:
| Meta is simple and elegant. I have just played with it to parse simple
| numbers etc, but have anybody used it to write parsers and translators
| for a full programming language? 

Way back ~1970 there was a PDP-10 program named "Meta II" that
was a standalone Meta processor. I used it to write a dead stupid
BLISS compiler over a single weekend! Now, granted, my compiler
emitted *dumb* PDP-10 assembler code[1], but it implemented most
of the core language. It didn't hurt that BLISS is roughly LL(1)
[if not LL(0)!], which nicely matches Meta's recursive-descent style.

Meta is cool.


[1] The code generator I wrote didn't bother with register management,
    assuming a simple stack VM, so that the code for "A = .A + .B * 3"
    turned into this horrid mess:  (*blush*)

	movei  t0,A	; get A's address
	push   p,t0	; save for later
	movei  t0,A	; get A's address, *again*! (oops)
	move   t0,(t0)	; get .A (contents of A)
	push   p,t0	; save for later
	movei  t0,B	; same song & dance for B
	move   t0,(t0)
	push   p,t0
	movei  t0,3	; get 3
	pop    p,t1	; get .B back
	mul    t0,t1	; .B*3
	pop    p,t1	; get .A back
	add    t0,t1
	pop    p,t1	; get A back [note: *address* of A]
	storem t0,(t1)	; done

    But of course, none of that was Meta's fault.  ;-}  ;-}

Rob Warnock, PP-ASEL-IA		<>
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