17 Feb 90
PDMSHELL.COM

   This is a small shell for ZCPR3.x systems to demonstrate one method of
enhancing (or at least changing) the appearance of our 8-bit systems using
the Pull-Down Menu features provided in the Version 4 libraries.  This
program requires a Termcap corresponding to the definitions in VLIB4D.

   As of the above date, this is a test version of the software, and has
not been completely debugged.  Any comments should be forwarded to the
author, or Joe Wright at Alpha Systems.

   PDMSHELL may be renamed, and will adapt itself to the new name for re-
invocation.

HOW IT WORKS.

   PDMSHELL accesses internal tables of program names and Menu Selection
headings, and relates user selections using the VLIB Version 4 routines to
program names.  It then builds a Command line consisting of; The selected
COM file name, optional arguments, a Semi-colon command separator, the
PDMSHELL program name and DU for re-invocation, and the target DU for menu
selections.  This command line is then prefixed into the Multiple Command
Line buffer and execution is passed to ZCPR 3.x.  An alternate way of doing
the same thing would have been to use the Shell Stack, but that is left for
another exercise.  Feedback would be welcome.

   Because both the DU for the PDMSHELL program and the target DU may be
entered, the program may be loaded from one location and logged into another
so that directory scans of the default directory will only display files in
the target DU.  Invocation is of the form:

		PDMSHELL [du:]

CONFIGURATION.

   Since this is a demo program, only limited menu support is provided
consisting of three Menu Bar headings and four Item Selections per heading.
The entries may be varied by entering the desired data into the PDMSHELL.OVL
file and assembling it to HEX.  It may then be loaded onto PDMSHELL.COM with
MYLOAD or the older MLOAD or equivalent programs.

				Harold F. Bower