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From: "Rod Pemberton" <dont_use_email@xnohavenotit.cnm>
Newsgroups: comp.lang.forth
Subject: Re: quick review of <BUILDS and CREATE history
Date: Tue, 21 Jan 2014 22:04:09 -0500
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On Tue, 21 Jan 2014 17:07:54 -0500, Elizabeth D. Rather  
<erather@forth.com> wrote:
> On 1/21/14 10:18 AM, Rod Pemberton wrote:

>> Sorry, yes, that should've had two colons which was, hopefully, obvious:
>>: : CREATE :NONAME DROP ...
>
> CREATE is inappropriate here. You want your word that builds a header.
> And :NONAME is also inappropriate because it returns the xt that youhave  
> to DROP. All you need to do is build the header, have a code
> field that points to DOCOL, and start the compiler.

I must've run into a problem somewhere.

It appears I backed out (CREATE) and these definitions:

: : (CREATE) COMPILE ENTER ] SMUDGE ;
: CREATE (CREATE) COMPILE DOVAR ;

I also had this definition for ; in another file paired with the
definition of : above:

: ; COMPILE EXIT SMUDGE [COMPILE] [ ; IMMEDIATE

It appears that (CREATE) when I backed it out is very similar to
the operations I have for :NONAME plus the BL WORD COUNT .. CMOVE
for name field in my : definition.

>> I have a low-level : and this would be for defining a new
>> high-level : in Forth.
>
> Why do you need 2 versions of : ?
>

I was attempting to eliminate the as much code in C as I could.
The idea was minimize as much non-standard behavior as possible by
having as little of the code in C as is possible.  If I can express
: in high-level Forth, I may be able to eliminate the bootstrap
version of : in C.

> There is nothing about a :NONAME to link.
>

I have to link "around" it.  I.e., the pointer used for linking could
be incorrect without a header for :NONAME.  Of course, it could
be correct also.  I don't know right now.  It gets updated somewhere
automatically.  I don't recall where I put that...  Sigh, I really
needed to review my code before discussing.

> Yes, the thing built by :NONAME has a code field, normally
> (in an ITC Forth) the address of DODOES, followed by the
> executable content.
>
> [...]
>
> An xt needs to be the address of the code required to execute the word.
> It has to be there for all words. That isn't what I'm calling the
> "header". A "header" consists of name and linking info.
>

Ah, the CFA is not part of the header...  So, words still have a CFA
without the header.

Sigh, I should've realized that.  The low-level "primitives" - because
they're in C - have NFA, LFA, DOES field, etc which can be placed after
the CFA and PFA by the C compiler.  The high-level Forth is compiled
sequentially.

Okay, that should mean the :NONAME definitions don't need a header.
It's still compiling an CFA, the ENTER.

> Hope this helps.
>

Yes.  Thanks.  I'm thinking what you said earlier should work.


Rod Pemberton