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From: ForthNet@willett.pgh.pa.us (ForthNet articles from GEnie)
Newsgroups: comp.lang.forth
Subject: Conventions and "tricks" used in Forth
Message-ID: <1812.UUL1.3#5129@willett.pgh.pa.us>
Date: 5 Oct 90 03:27:27 GMT
Organization: String, Scotch tape, and Paperclips.  (in Pgh, PA)
Lines: 32


 Date: 09-27-90 (12:24)              Number: 3860 (Echo)
   To: IAN WATTERS                   Refer#: 3858
 From: CHARLIE HITSELBERGER            Read: NO
 Subj: HASHING THE DICTIONARY        Status: PUBLIC MESSAGE

 Here's my function to hash the dictionary.  It's go [garbage in
 message elided. -dwp]
eal thing, but for all you deprived souls without a 6502, here's
 the high-level def.

 : HASH   ( ADDR -- N ; assume a counted string address )
     0  OVER C@  127 AND  1+  0
     DO 
         OVER  I +
         C@  XOR
     LOOP
     SWAP DROP 
     16 /MOD  XOR ;

 Now, for my next trick, I'll create a table of 16 words at the very
 bottom of the dictionary.  These words will point to the last word in
 the dictionary for that particular hash-thread.  All hash threads will
 wind up by pointing to the lowest word in the dictionary, which in turn
 will link to a "0000" (end of linked list).  I figured that was cleaner
 to link everything into one tail, rather than to have 16 vocabulary
 tails.  Please, somebody, stop me if I am a fool.  I have never rolled a
 compiler before, and I go to sleep every night with the nagging feeling
 that somehow I am really messing this up and will regret it later.
-----
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