[comp.lang.forth] The Beauty of Postfix

pyr75@psc90.UUCP (Adam Crossland) (08/26/88)

In article <2768@pt.cs.cmu.edu> koopman@a.gp.cs.cmu.edu (Philip Koopman) writes:
[Good stuff deleted for reasons of brevity.]
>One of the most useful aspects of Forth is implicit parameter
>passing.  
[More stuff ^W'd.]
>
>The arithmetic operators are treated as subroutines just like
>any other word.  This allows a blurring of the distinction between
>hardware supported primitives and high level routines, improving
>transportability and making optimization of inner loops in
>assembly language or microcode quite easy.
>So, to me, the RPN notation is just an inconvenient side-effect
>of the implicit parameter passing mechanism used by the language,
>and is not really an important feature itself.

[See above]
>Phil Koopman         koopman@faraday.ece.cmu.edu  Arpanet
>Student at CMU, sometime consultant to Harris Semiconductor.

Yes!  Phil has done this discussion a great service by expressing
very well the fundamental principle that gives Forth its beauty,
elegence and Buddha-nature.

The stack.  Stacks are wonderful things, and they underlie almost
everything that goes on in Forth.  I am sure that Forth was not
designed to utilize postfix notation, but it is surely the case that
the design itself made RPN the natural choice.

The stack is to Forth what the Grand Unifying Field is to physics.
Well, sort of.  Anyway, you should understand the idea.

Forth is a work of art, not just a programming language.

					    Adam A. Crossland