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From: wmb@MITCH.ENG.SUN.COM
Newsgroups: comp.lang.forth
Subject: Re: ANS TC Magnet for Interpreter
Message-ID: <9008310123.AA28936@ucbvax.Berkeley.EDU>
Date: 30 Aug 90 06:50:31 GMT
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Reply-To: wmb%MITCH.ENG.SUN.COM@SCFVM.GSFC.NASA.GOV
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  Subject: BASIS12 input-stream definitions

Robert Berkey writes:
> ... a careful and detailed analysis of the input stream definition,
> exposing some inconsistencies.

Robert,

Based on your analysis, I suppose that it is incumbent on someone
to take a shot at rewording this section of Basis to make it clear.
I guess it might as well be me.  Wanna help?

According to my understanding of the way it is *intended* to work,
your QUOTE-TO could should be perfectly correct.  We need to make
sure that the words indeed say that.

>   (3) The original source of my concern about setting >IN stemmed from
>   the rationale note that says, "Re-reading the input stream by
>   setting the contents of >IN to some arbitrary value, such as zero,
>   is incorrect."  This seemed to imply that it's a system perogative
>   as to what goes into >IN .

The intention of this rationale was to emphasize that you cannot assume
that the current input stream began at TIB + 0.  Note that it says
"re-read".  It is my understanding that it is fair game to set >IN
to the value  "adr TIB -" to begin reading at "adr".

Let's take a shot at fixing the language.


>   The intent is presumably that systems can change the value returned
>   by TIB .  If so, when does it change?

My understanding is that it changes only when the system switches from
one line-oriented input stream source to another, as with EVALUATE .
When a nested interpreter (e.g. EVALUATE , LOAD) exits, the previous
value of TIB is supposed to be restored.


>   Without this information, programs cannot use TIB .

You can use it within the context of one input stream source.


>   (5) The word SOURCE-FILE doesn't exist in BASIS12.

That was an editing mistake.  I hope you guys fixed it at Vancouver?
Please say yes.  In my letter to Elizabeth, recording my votes, I
stated 2 times that the effects of TP-641 (SOURCE-FILE, etc) did not
appear in either Basis 11 or Basis 12.

If this didn't get fixed, then I am depressed, and all that trouble
that I went to to FAX my comments was wasted.

Mitch