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From: ForthNet@willett.pgh.pa.us (ForthNet articles from GEnie)
Newsgroups: comp.lang.forth
Subject: ANS TC Magnet for Vocabularies and :
Message-ID: <1540.UUL1.3#5129@willett.pgh.pa.us>
Date: 16 Aug 90 11:47:45 GMT
Organization: String, Scotch tape, and Paperclips.  (in Pgh, PA)
Lines: 61


 Date: 08-13-90 (16:55)              Number: 3646 (Echo)
   To: BRAD PEPERS                   Refer#: NONE
 From: CHRIS WATERS                    Read: NO
 Subj: LATEST                        Status: PUBLIC MESSAGE

 Ah, we seem to be having troubles somewhere in the net with at-signs.
 This problem is related, I think, to a particular brand of BBS, PCBoard,
 used by many nodes on at least two of the networks here.

 Note to all Forth users.  PCBoard has real problems with this character,
 and cannot be recommended to Forthers.  For this message, I'll use ...
 er, '&' to represent the at-sign.  Sorry if this is confusing.  I'm
 currently in the middle of a discussion (read: fight) with the network
 administration about this issue.

 BP:What is the 'proper' defn of LATEST?
  3
  3    1)  : LATEST CONTEXT & & ;
  3 or 2)  : LATEST CURRENT & & ;
  TMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM

 Brad, I'm glad you put 'proper' in quotes.  There are good reasons for
 the fact that LATEST has not been part of any standard since figForth.
 Consider this definition:

 VOCABULARY USELESS
 USELESS DEFINITIONS
 : WASTE ... ;
 FORTH DEFINITIONS IMMEDIATE

 Depending on how your Forth is implemented, this will either make WASTE
 an IMMEDIATE word, or will make most recent definition in FORTH
 immediate.  A strict reading of the 79- or 83-standards allows only the
 former, but if IMMEDIATE uses LATEST, a common method of implementation,
 and LATEST is defined by either of your methods above, the latter will
 take place.  For this reason, many systems, including all I have
 implemented, use a user variable, LAST, to point to the most recently
 defined word in any vocabulary.  I don't even include LATEST in my
 Forths, as LAST & (at) suffices.

 In figForth, CURRENT & & (at at) was used in enough different places to
 justify making it a separate word.  In the 79- and 83-standards, some
 words must refer to CURRENT & & (at at), while others must refer to
 LAST & (at) or some equivalent, in order to avoid the bug above.

 So, the real answer to your question is:  CURRENT & & (at at) is the
 commonest definition for LATEST, but any definition is acceptable for
 this non-standard word.

 Hope this clears things up.  Happy Forth-ing,

 Chris

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