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From: "Rod Pemberton" <dont_use_email@xnothavet.cqm>
Newsgroups: comp.lang.forth
Subject: Reduce dictionary lookups using LIT ?
Date: Tue, 01 Jul 2014 20:24:36 -0400
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Reduce dictionary lookups using LIT ? ...

I saw a quote from a Forth book which said LIT was also
useful to eliminate dictionary lookups of numbers when
loading and compiling a vocabulary.

So, instead of:

: ONE 1 ;  \ LIT compiled by innner interpreter

this would be used in a vocabulary:

: ONE LIT 1 ;  \ LIT explicitly used

Here, 1 is not searched for in the dictionary by the inner
interpreter when compiling ONE due to the use of LIT .

I'd like to use that syntax in my vocabulary, but I think
it creates some problems.  I already have a historically
based run-time LIT which works differently.

A new "high-level" LIT as used in ": ONE LIT 1 ;" would
need to be something like the following:

: LIT BL WORD NUMBER POSTPONE LITERAL ; IMMEDIATE

Except, LITERAL calls the original run-time LIT:

: LITERAL POSTPONE LIT , ; IMMEDIATE
: LIT R> DUP "cell_adjustment" >R @ ;

This creates a name conflict between the two LITs, since
my vocabulary would need to use both at the same time.

A common option in such naming conflict situations is to
rename the run-time, wrapping it in paren's, e.g.: (LIT) .
Except, I don't want to change the historical name of the
original run-time LIT .  It seems to be well accepted.

So, is there a common name for such a high-level LIT?
Or, was there a version of LIT that did both?
And, is this technique even used anymore?


Rod Pemberton