Path: utzoo!attcan!uunet!willett!ForthNet
From: ForthNet@willett.UUCP (ForthNet articles from GEnie)
Newsgroups: comp.lang.forth
Subject: F-PC Forth Tutorial
Message-ID: <1030.UUL1.3#5129@willett.UUCP>
Date: 29 May 90 03:24:29 GMT
Organization: Latest link in the ForthNet chain.  (Pgh, PA)
Lines: 106


 Date: 05-27-90 (14:31)              Number: 14 (Echo)
   To: JACK BROWN                    Refer#: NONE
 From: ROY RICE                        Read: NO
 Subj: LESSON3                       Status: PUBLIC MESSAGE

 Jack: Here is a beginning on lesson 3. I used the f-pc editor and put it
 into seq file format so that I could test it easily while working.
 \ RARL3.seq
 \ Lesson 3 ex.1 -6
 \ Roy Rice, 3848 Fox Glen Ct., Atlanta, Ga.30319   404-451-0079
 comment:
 Jack, I hope that it is OK to jump in at lesson 3. I have had some
 experience with Forth, and think that I am familiar with most of the
 basic words. I do need a lot of work on the more advanced items, though
 and am looking forward to future lessons and the conversion of the
 current ones to version 3.5. Thanks for providing this course!
 comment;

 \ from lesson 3, part 1:
 : .SD ( -- )
      DEPTH ?DUP IF
                  0 ?DO DEPTH I - 1- PICK
                        DEPTH I - 2- PICK
                        D.  8 EMIT ASCII . EMIT
                  2 +LOOP
                 ELSE ." Empty" THEN ;

 \ L3P2, ex 1:
 : .SS ( -- )  \ print all single numbers on stack
      DEPTH ?DUP IF
                  0 ?DO DEPTH I - 1- PICK
                        .  8 EMIT ASCII . EMIT
                  LOOP
                 ELSE ." Empty" THEN ;

 \ L3P2 ex 2:
 : .SD2 ( -- ) \ print stack as double #s if depth is even, as single if 
 odd
         DEPTH  ?DUP  IF
                      2 MOD  ( -- 0|1 ) \ 1 if depth is odd
                         IF  .SS
                         ELSE  .SD   THEN
                 ELSE ." empty"    THEN   ;

 \ L3P2 ex3.3:
 : MY2SWAP ( a, b, c, d -- c, d, a, b)
         3 ROLL 3 ROLL  ;
 : MY2DROP ( a, b -- )
         DROP  DROP  ;
 : MY2DUP  ( a, b -- a, b, a, b )
         OVER OVER  ;
 : MY2OVER ( a, b, c, d -- a, b, c, d, a, b )
         3 PICK 3 PICK  ;
 : MY2NIP  ( a, b, c, d -- c, d )
         ROT DROP ROT DROP  ;
 : MY2TUCK ( d1, d2 -- d2, d1, d2 )
         MY2SWAP MY2OVER ;
 : MY2ROT  ( d1, d2, d3 -- d2, d3, d1 )
         5 ROLL 5 ROLL   ;
 : MY-2ROT ( d1, d2, d3  -- d3, d1, d2 )
         MY2ROT MY2ROT  ;

 comment:
 results of ex3.4:


  C - 35k : - 49k   Depth 6     B:\lesson3\RARL3.SEQ                     
  19:59
 3. 4. .sd2 3.  4.   ok                                                  
 FORTH
 myy2swap .sd 4.  3.   ok                                               
 FORTH
 my2drop .sd 4.   ok                                                   
 FORTH
 5. .sd 4.  5.   ok                                                    
 ROOT
 my2dup .sd 4.  5.  5.   ok
 my2nip .sd 4.  5.   ok
 my2over .sd 4.  5.  4.   ok
 my2drop .sd 4.  5.   ok
 my2nip .sd 5.   ok
 6.  ok
 .sd 5.  6.   ok
 my2tuck .sd 6.  5.  6.   ok
 my2drop 4. .sd 6.  5.  4.   ok
 my2rot .sd 5.  4.  6.   ok
 my-2rot .sd 6.  5.  4.   ok

 EX3.5 Still need some work on floored division for negative numbers!
       Will review lesson 2 further.
 comment;

 \ ex.3.6:

 : D1+ ( d -- D+1 )   1. D+ ;
 : D2+ ( d -- d+2 )   2. D+ ;
 : D1- ( d -- d-1 ))   1. D- ;
 : D2- ( d -- d-2 )   2. D- ;
 comment:
 : D2* ( d -- 2d )     2 *D  ;
 this won't work, because *D takes a 16 bit integer as its argument.
 Hoe visual editor!
-----
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