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On Tue, 2005-02-01 at 05:15, David Olofson wrote:
> On Monday 31 January 2005 17.15, Mark Hamburg wrote:
> > Not applicable to Lua without whacking pretty much everything, but
> > Forth is very interesting 

> That means operations and operands are inherently lists, rather than 
> trees? 

Forth is Lisp backwards. It uses reverse polish 
(postfix) notation:

	1 2 add   -- forth
	1 + 2     -- C
	(add 1 2) -- Lisp

This means the grammar of Forth, like Lisp, is very simple:

	word = word *

is the whole of it. This has the property that for any
sequence of words  you can define a subroutine, 
and replace the sequence by the subroutine.

Note Forth is heavily used today..  Postscript IS forth.

The forth execution model is also very simple:

(a) if it is a number, push it onto the stack
(b) otherwise execute it

John Skaller,
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snail: PO BOX 401 Glebe NSW 2037 Australia
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