Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uunet!willett!ForthNet
From: ForthNet@willett.UUCP (ForthNet articles from GEnie)
Newsgroups: comp.lang.forth
Subject: ANS TC Magnet for LOOPS, EXIT, Term.
Message-ID: <578.UUL1.3#5129@willett.UUCP>
Date: 27 Feb 90 23:55:36 GMT
Organization: Latest link in the ForthNet chain.  (Pgh, PA)
Lines: 38


 Date: 02-26-90 (08:19)              Number: 2974 (Echo)
   To: STEVE PALINCSAR               Refer#: 2965
 From: IAN GREEN                       Read: NO
 Subj: DO LOOPS IN FORTH             Status: PUBLIC MESSAGE

    The reason for using FOR-NEXT is that I saw a comment comparing FOR 
 vs. DO in the RTX2001 data sheet. It said FOR runs several times faster 
 so I assumed that this was a standard word in Forth.

 >Ian, you're probably looking for something like this:
 >: LOOP_DEMONSTRATION  ( n2 n1 -- )
 >\ That is, both the inner and outer loop limits are on the stack
 >\ before this word executes.  You could put them there by fetching
 >\ from a couple of variables, or whatever other means you like.
 >   1 DO        ( Takes n1 from param stack, puts in on Rstack )
 >      1 DO     ( Takes n2 from param stack, puts it on Rstack )
           <SOMETHING>  ( whatever you want to execute )
 >      LOOP
 >   LOOP  ;
 >
    In the help conference I saw a note that described a different 
 syntax. It used the FOR-NEXT syntax and demonstrated the control 
 variable (I need to be able to use the control variable inside the loop)
 and it like your code used a 1. My question, what does the 1 do?

 The code was something like

 : FORSAMPLE 1 M FOR wordsequence NEXT ;

 Eventually I will get this together. Thanks

 Ian Green

 NET/Mail : British Columbia Forth Board - Burnaby BC - (604)434-5886   
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