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Date:	Wed, 6 Aug 2003 22:30:57 PDT7
From:	"Lynn H. Maxson" <lmaxson@pacbell.net >
Reply-To:	scoug-programming@scoug.com
To:	< "scoug-programming@scoug.com" > scoug-programming@scoug.com >
Subject:	SCOUG-Programming: Re: Warpstock 2003 Presentation

Content Type: text/plain

"...But I don't understand what you've said in the above
paragraph."

RPN allows you to write parenthesis-free expressions. It does
so in a manner which minimizes register usage (load and
store). Thus it produces an optimal code sequence.

Burroughs implemented a stack architecture with their B5000,
demonstrating the efficiency of converting non-RPN
expressions in source code (in their instance BALGOL) to RPN.
Thus they achieve temporary performance advantage over
compilers which didn't, which included IBM's. It didn't take
long for IBM to react. After all as one IBM engineer noted the
entire stack architecture of the Burroughs machine required
all of three 7090 instructions, two of which were "load
register" and "store register". The third eludes me.

To get back to an earlier point maybe the Burroughs
engineers intuitively proved the value of RPN, but after that
point intuition was out and copying was in.

Any book on Forth should illustrate this point. Perhaps the
best overall description exists in W. H. Burge's "Recursive
Programming Techniques" in describing a SECD machine
(Stack, Environment, Control, and Dump). I have an extra
copy I could loan you...if ever you deign to join us in the
future.

If at any time in the future we seem to be communicating on
the same wavelength as a regular habit, then I might hold out
for use of English as a specification language. Until then my
general reaction is no, no, no...and no. Blair talks about
ambiguity. Ambiguity itself represents an extension to
operator overload.

We are agreed that more people should program. That more
do in SQL than any other language and that it's based in logic
programming ought to serve as something of a clue.

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