9 Jan
2014
9 Jan
'14
3:21 p.m.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of Paul Koning
Sent: Thursday, January 09, 2014 10:07 AM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Lisp does NOT use RPN - Re: cctalk Digest, Vol 125, Issue 13
Forth is postfix notation, because the Forth execution model is a stack
machine with the Forth ?words? corresponding directly to the execution of
primitive operations that act on the stack. Forth is really an assembly
language rather than a high level language; those familiar with Burroughs
mainframe machines will see the analogy with the machine language of
those systems.
I respectfully disagree that it is appropriate to refer to Forth as 'an assembly
language'. Forth is a threaded interpretive language, written in any of several
assembly languages. Burroughs was interesting in that it performed a great deal of
language processing in hardware - we have a Unisys V380 (a rebadged/remicrocoded B4955)
whose machine instructions map almost one for one onto COBOL verbs. I'm aware of
processors that were likewise designed to do much of the lifting of parsing Forth in
hardware, but Forth itself is at a higher level (although not much higher!). -- Ian