




            FORTH-83: INTRODUCTION AND BRIEF HISTORY


      FORTH  is a computer language (and in many implementations
 an operating system) characterized  by  an  Extensible  reverse
 Polish  syntax  and  usually implemented with indirect threaded
 code.  It was invented by  Charles  H.  Moore  about  1969  for
 control   and  data  collection  in  a  large  radio  telescope
 installation.  It has since proved  to  be  very  powerful  and
 versatile.

      FORTH-83  is  a  standard  version  of  the Forth Language
 published by the Forth Standards  Team  in  1983  to  supercede
 FORTH-79.   The standard document is available (along with lots
 of other Forth literature) from Mountain  View  Press,  P.O.Box
 4656,  Mountain View, CA 94040 ($15).  The standard may also be
 copied from someone who has it (under the terms granted on  the
 copyright page).

      The  "F83"  programs  in  the  FORTH  section are a public
 domain implementation of  FORTH-83  (note  the  distinction  in
 names   to   distinguish  the  standard  from  this  particular
 implementation).  Rather than  being  a  stand-alone  operating
 system  it  runs under CP/M.  Versions for IBM compatibles, MS-
 DOS compatibles, and Apple are also  available  (consult  local
 FIG, below).

      "F83" was written by Henry Laxen and Michael Perry, two S.
 F.   Bay   area   Forth  systems  programmers  of  considerable
 experience whose names appear in block 0 of several of the .BLK
 files.  They graciously have placed it in  the  public  domain.
 One  tutorial  book of value for F83 is "FORTH TOOLS, Volume 1"
 by Anita Anderson and Martin Tracy [MicroMotion, 12077 Wilshire
 Blvd., #506, Los Angeles, CA 90025 (213)821-4340].


                            USING F83


      To get started, take the F83.COM file and  as  many  *.BLK
 files  as  you  have  room  for.  To avoid hours of modem time,
 consider getting the disks copied through the Heath  SIG  which
 sponsors this BBS.

      Load  F83  as any other .COM file, and if you furnish it a
 filename on the command line, that file will  be  opened  auto-
 matically as a block file:

         F83  FORTH.BLK c/r.

 Once in F83 type:

         n LIST c/r

 where  n  is  a Screen <block> number,  and that screen will be
 displayed.  Or type:







                               -2-


         VOCS  c/r

 and Forth will list the vocabularies.  To see the  words  in  a
 vocabulary such as the editor, type:

         EDITOR WORDS c/r

 and it will list them, last defined word first.  To look at the
 code for a particular word, type

         VIEW wordname c/r

 and  if  the correct .BLK file is present on the default drive,
 its source code will appear.  Then  if  you  want  to  see  the
 "shadow  screen"  documentation,  be sure you are in the editor
 vocabulary:

         EDITOR c/r (if you weren't already in Editor)

 and type:

         A L c/r.

 The "A" means Alternate between source  and  documentation  and
 the  "L" relists the block (=screen) currently pointed to.  The
 mechanism for this is that the first half  of  a  block  (.BLK)
 file  is  source  code and the second half, block for block, is
 documentation.

      If you are using an H/Z-19/29/89, the first time in EDITOR
 you should execute

         HEATH c/r

 to configure the editor for your terminal.  Others should  look
 for  corresponding  words  for  their  terminals  (FALCO, ANSI,
 PERKIN, and DUMB).  The  editor  is  largely  as  described  in
 "Starting  FORTH"  by Leo Brodie (Prentice-Hall). This book was
 written with  FORTH-79  in  mind,  so  it  is  not  a  complete
 reference for FORTH-83.

      I  have  a  full  screen  editor which works with the H/Z-
 19/29/89 and user documentation for it,  but  they  aren't  yet
 polished  enough to put on the BBS.  If you want those files or
 have questions, you may leave mail on this BBS for DEEJAY.   Be
 patient-- I only call in every two weeks or so.

      The  local  Forth  Interest  Group/Forth SIG of SDCS meets
 every Thursday at NOON at Convair Recreation  Center  (CRA)  on
 Missile  Road, just South of Thearle's Music Store on Clairmont
 Mesa Rd.  Bring sack lunch and any questions you may have.


                                 May the Forth be with you.







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