README.RXVT4APL

"Max H. Parke" <ikj1234i@yahoo.com> has modified the
commadpt driver so APL works properly with rxvt4apl.

rxvt4apl is an 8-bit clean, colour xterm replacement
that has been optimised for use with openAPL.

Here is Max's README regarding his rxvt4apl mods:


1. The rxvt4apl package provides a set of extensions to enable both
entry and display of the complete APL character set including the 
characters without ASCII equivalents.  Although we use the standard version
of rxvt4apl [2.4.5] without modifications, there is a small bugfix patch
(below) if necessary.

2. Once rxvt4apl has been installed and tested (there are several required
materials in openAPL such as X11 fonts and keymaps), you should connect
using telnet to the listening port for the terminal in hercules:
    telnet localhost 57413
then type the standard APL command to sign on
    )1234
There is extensive helpful documentation with openAPL if you have problems
with X11 fonts or keymaps, etc.

3. Rather than use the right ALT key I used the unused "windows" key for
the Mode_switch key in modeswitch.xmap:

clear Mod5
clear Mod4
clear Mod3
keycode 133 = Mode_switch
add Mod3 = Mode_switch

4. The terminals must be defined to hercules using the conf file definitions
0402 2703 dial=in lport=57413 lnctl=ibm1 term=rxvt4apl skip=5EDE code=ebcd iskip=0D0A prepend=16 append=5B1F eol=0A binary=yes crlf=yes sendcr=yes

5. In general when typing a character, rxvt4apl seems to prefer to use
the standard ASCII character if it exists, in preference to the APL
character.  So for example if you wish to enter the apostrophe (') use 
your ASCII keyboard's standard apostrophe key, not APL's apostrophe
(ordinarily shift-K).

6. In this implementation the standard alphabet APL characters A-Z must
be typed as lowercase ASCII characters to be properly translated on 
input.  Also, rxvt4apl is missing the underlined alphabet characters...

7. Overstrike handling is supplied in this driver release, although they can
be formed by entering the individual characters separated by the backspace
key.  The display will not be correct but the overstrike sequence will be
properly received by APL\360.  Better is to enter the overstrike characters
using the rxvt4apl composite characters; when this is done the driver will
convert these extended-ASCII characters into the proper overstrike sequences
used by APL\360 on input (the extended characters are converted into three-
character sequences in 2741 code, with the middle character in the sequence
being the backspace character).  On output, the driver replaces the third 
character in the overstrike sequence with the correct rxvt4apl extended-ASCII
character.

8. Many quirks exist - a couple of examples:
 - the right arrow key (branch command) must be hit twice
 - Some commands such as up and/or down grade cause unexpected escape 
   to telnet command mode, even in binary mode

9. If you receive this error when running rxvt4apl
     can't open pseudo-tty
try the following patch (required for recent ubuntu)

======================= START OF PATCH ====================
--- rxvt4apl_2.4.5/src/command.c        1998-01-01 14:29:08.000000000 -0500
+++ rxvt4apl_2.4.5-patched/src/command.c        2012-12-06 13:48:12.698068063 -0500
@@ -448,7 +448,7 @@
     ptydev = ttydev = _getpty(&fd, O_RDWR | O_NDELAY, 0622, 0);
     if (ptydev == NULL)
        goto Failed;
-#elif defined (__svr4__)
+#elif 1 // defined (__svr4__)
     {
        extern char    *ptsname();
 
======================= END OF PATCH ====================