Path: utzoo!attcan!uunet!lll-winken!csd4.milw.wisc.edu!mailrus!wasatch!thomson
From: thomson@wasatch.utah.edu (Rich Thomson)
Newsgroups: comp.lang.forth
Subject: Re: Setting cursor routines for the Forth editor
Message-ID: <1888@wasatch.utah.edu>
Date: 23 May 89 06:45:09 GMT
References: <8905221311.AA00762@lilac.berkeley.edu>
Organization: Oasis Technologies
Lines: 72

In article <8905221311.AA00762@lilac.berkeley.edu> PAWELKDA@UREGINA1.BITNET
    (Darrel Pawelka) writes:
> Presently I need help in setting up the cursor routines necessary for the
> in-built [sic] Forth editor to work with my Zenith Eazy-PC terminal/monitor
> combination.

Well, I can't help you out on the exact terminal escape codes for your
system, but somewhere in your docs should be a description of the escape
codes and how they're interpreted for your system.  I can, however, give
you some enlightenment on what the ADM-3A example is doing.

> The instructions give as an example how to tell Forth about the cursor
> routines for an ADM-3A terminal.
>
>1 EDIT<CR>
>10MAR84HHL<CR>
>0 NEW<CR>
>\ CURSOR ROUTINES FOR AN ADM-3A TERMINAL<CA>
>EDITOR DEFINITIONS<CR>
>: ADM-AT<CR>
>   27 EMIT  ASCII = EMIT   32 + EMIT   32 + EMIT   ;<CR>

AT is the cursor placement routine.  Presumably it takes x and y
coordinates on the stack.  ``27 EMIT'' sends an ESCAPE character to your
output device.  In general, n EMIT outputs character code n.  ASCII reads
the next space delimited word in the input string and pushes the ascii code
for that word (which should only be a single character).  So, from this you
can deduce that the escape code sequence for positioning the cursor on an
ADM-3A would be in basic (ugh):

    CHR$(27);"=";CHR$(32+x);CHR$(32+y)

>: ADM-DARK<CR>
>   CONTROL Z EMIT   ;<CR>

Similarly, CONTROL is a word that turns the next word in the input string
to a control character, so ``CONTROL Z'' pushes ascii code 26 onto the
stack.

I'd say what you need to do is to find the escape sequence table for your
monitor and create some new words that emit the proper escape sequences for
the actions the editor wants to perform.

>: ADM-3A<CR>
>   ['] .ALL      IS  .SCREEN <CR>
>   ['] ADM-AT    IS  AT <CR>
>   ['] ADM-DARK  IS  DARK <CR>
>   ['] NOOP      IS  -LINE <CR>
>   ['] (BLOT)    IS  BLOT ; <CR>

This part replaces the old definitions for ``.SCREEN'', ``AT'', ``DARK'',
``-LINE'' and ``BLOT'' and replaces them by the appropriate things for an
ADM-3A.  You want to do this because the editor is calling .SCREEN, AT,
etc.  You are effectively back-patching the hooks into the screen driver
that the editor uses.

Hope all this helps you somewhat.

						-- Rich
[ Editor of the Amiga FORTH Programmer's Newsletter;
  Send add requests to: amiga-forth-request@cs.utah.edu
  Send submissions  to: amiga-forth@cs.utah.edu ]

Rich Thomson	thomson@cs.utah.edu  {bellcore,hplabs}!utah-cs!thomson
"Tyranny, like hell, is not easily conquered; yet we have this consolation with
us, that the harder the conflict, the more glorious the triumph. What we obtain
too cheap, we esteem too lightly." Thomas Paine, _The Crisis_, Dec. 23rd, 1776
-- 
Rich Thomson	thomson@cs.utah.edu  {bellcore,hplabs}!utah-cs!thomson
"Tyranny, like hell, is not easily conquered; yet we have this consolation with
us, that the harder the conflict, the more glorious the triumph. What we obtain
too cheap, we esteem too lightly." Thomas Paine, _The Crisis_, Dec. 23rd, 1776