Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!uunet!willett!ForthNet
From: ForthNet@willett.UUCP (ForthNet articles from GEnie)
Newsgroups: comp.lang.forth
Subject: ANS TC Magnet for Interpreter
Message-ID: <260.UUL1.3#5129@willett.UUCP>
Date: 14 Jan 90 03:54:56 GMT
Organization: Latest Link in ForthNet Chain (Pittsburgh, PA)
Lines: 77

Category 10,  Topic 24
Message 5         Sat Jan 13, 1990
R.BERKEY [Robert]            at 17:29 PST
 
 
 To: Mitch Bradley
 Re: Context-Free Numeral Syntax

 MB> Of course, Forth really ought to have some way of explicitly
 MB> declaring the radix of an individual number.

So far, so good.  One of the single biggest annoyances I've encountered
recently is being unable to read code because of the context sensitivity of
BASE .



 MB> The consensus was that I should amend the proposal to instead
 MB> define Forth words H# and D# , which would be followed by a
 MB> space and the number.  We'll see how this amended proposal
 MB> fares.


As for H# and D# as prefix words, I can't tell that the committee isn't just
putting you off:

(1) These can easily enough be defined.

(2) The association of 'D' with "double" compounds problematically its use for
decimal.  Precisely the name D# is used for interpreting the following string
as a double number, and the FST standards offer no other way but prefix
operators for double numbers in source code.  I've come up with the Roman
numeral 'X' for the ten of DECIMAL as a fix (only to discover other's using
'X' for hex!).

(3) I've known about these prefix operators for some nine years now, but I've
_never_ used them.

(4) Did they agree that these words would be state smart?   ;-)

 : H#12a4   ( -- $12A4 )   \ Define a constant a hard way
    STATE @ IF    [H#] 12A4 POSTPONE LITERAL
    ELSE          [  H# 12A4 ] LITERAL
    THEN ; IMMEDIATE



 MB> At the last ANSI meeting, I proposed that number syntax
 MB> should allow the prefixes H# , D# , O# , and B# ...
 MB> Thus you could write H#12a4 or D#5478 ...

Back to standardizing H# and D# and B# and O# as a part of the number:  Part
of my negative response to this syntax would have to be that I haven't seen it
before, but I think there is more to it.  Are you claiming you use these?  Can
you say you like them?

   ---  Single character syntax ---

Indeed, do you know of more than one character ever having been used in any
assembler, language, etc.  It seems that any of the single characters " # % &
or ' would suffice.

For my own solution with F-PC I've not resisted the culturally-biased '$' for
hex, and adopted '#' for decimal, i.e., $12A4 and #32 .  It was work to go
through and mark each number, but the effort was well worth it.  In short,
I've eliminated HEX and DECIMAL from application code.

Guy Kelly's PC83 uses a logical relationship of "'" for octal and '"' for hex.
I've heard that single character syntax has been in the San Diego systems
since pre-FIG days (and there was such in the SuperForth/polyFORTH I used
there).  They wonder why the rest of us haven't caught on yet!

Robert Berkey

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