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From: "Rod Pemberton" <bork@lllljunkqwer.cpm>
Newsgroups: comp.lang.forth
Subject: Re: FORTH - How Does It Work?
Date: Mon, 04 May 2015 20:01:11 -0400
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On Mon, 04 May 2015 15:13:36 -0400, Albert van der Horst  
<albert@spenarnc.xs4all.nl> wrote:

> Well the OP suggest this to people who want to know how Forth
> works on the inside. An alternative is to randomly start SEE-ing
> some code in a Forth you use.
> For an extreme example take this:
>
> Gforth 0.7.0, Copyright (C) 1995-2008 Free Software Foundation, Inc.
> Gforth comes with ABSOLUTELY NO WARRANTY; for details type `license'
> Type `bye' to exit
> SEE TO
> noname :
>   ' dup >definer 140003129076120 >definer =
>   IF     16 + !
>   ELSE   -32 throw
>   THEN ;
> latestxt
>
> noname :
>   COMP' drop dup >definer 140003129076120 >definer over =
>   IF     drop 16 +  POSTPONE ALiteral 6396632 compile,
>   ELSE   140003129105440 >definer over =
>          IF     drop 6397824 compile, 16 + @ lp-offset, 6396656 compile,
>          ELSE   140003129105608 >definer over =
>                 IF     drop 6397824 compile, 16 + @ lp-offset, 6396632  
> compile,
>
>                 ELSE   140003129105496 >definer over =
>                        IF     drop 6397824 compile, 16 + @ lp-offset,  
> 6396664
>                               compile,
>                        ELSE   140003129105552 >definer over =
>                               IF     drop 6397824 compile, 16 + @  
> lp-offset,
>                                      6397288 compile,
>                               ELSE   -32 throw drop
>                               THEN
>                        THEN
>                 THEN
>          THEN
>   THEN ;
> latestxt
> interpret/compile: TO  ok
>
> Compared to Ting's books this is pretty intimidating.
> Of course you're right that Forth is not defined by an implementation,
> and this example serves to show how different implementations are,
> but traditionally (some) people *are* interested in how one manages to
> make a compiler/interpreter.
>

It seems that the constants beginning with digit '6' might be XTs
due to COMPILE, .  I could guess that >DEFINER takes the constants
which begin with '14', but what is >DEFINER ?

Are the large constants the XTs of primitive words?
Are they the XTs of NONAME words?

Can I execute '6397824'?  (Yes.)
Can I execute '140003129105440'?  ...
Can I display their name or SEE their code?


Rod Pemberton

-- 
Cars kill more people than guns in the U.S.
Yet, no one is trying to take away your car.