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From: wmb@MITCH.ENG.SUN.COM
Newsgroups: comp.lang.forth
Subject: Vocabularies
Message-ID: <9011051456.AA28156@ucbvax.Berkeley.EDU>
Date: 5 Nov 90 04:29:56 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Reply-To: wmb%MITCH.ENG.SUN.COM@SCFVM.GSFC.NASA.GOV
Organization: The Internet
Lines: 40

> If the semantic difference between VOCABULARYs is sufficient to break
> code, then the semantic difference between WORDSET and VOCABULARY is
> likewise sufficient, and you can't fix it with a global search
> and replace.

> Or was it your intention to have each transitional system implement two
> different vocabulary mechanisms?

There are 3 cases to consider:

1) A system where the semantics of that system's VOCABULARY are the same
   as WORDSET .  Examples: F83 , F-PC

        Resolution:  : VOCABULARY WORDSET ;  and everybody is happy.
        Old code still works, new code can use WORDSET and be portable.
        Or do the global search-and-replace.

2) A system where the semantics of VOCABULARY are different from WORDSET .
   Examples: FIG-Forth, MVP-FORTH, MAC Forth, LMI Forth, polyFORTH.

        Resolution: The system vendor will support both VOCABULARY ,
        meaning whatever it has always meant on that system, and also
        WORDSET , meaning what ANS Forth says it means.  Customers
        will not revolt, because their old code will still work, and
        they can migrate to the portable use of WORDSET as desired.

3) Brand-new systems, with no installed base:

        Resolution: Implement WORDSET .  If compatibility with some
        existing system is needed, for marketing reasons or whatever,
        implement VOCABULARY to be compatible with the desired system.

With WORDSET , most people lose a little bit (i.e. they have to learn
a new word, or a modest amount of memory is wasted).  If VOCABULARY was
chosen, some people wouldn't lose at all, and others would lose a lot
(i.e. either their system vendor would choose not to implement ANS Forth
for fear of alienating his existing customers, or their programs would
break in hard-to-isolate ways).

Mitch