Active aliasing in the text editor (Word Processor) application
===============================================================

Introduction
------------

This document explains the special modes of the S3/S3a text editor
(Word Processor) application which can be accessed by passing
suitable "alias information" on the command line.

As well as being placed on the command line, this alias info can also
be defined in .ALS or .MA files (a .MA file is a text file that can
be operated on by a tool MakeAls.exe to produce a .ALS file).  When
the System Screen starts an aliased application (one defined by a
.ALS file instead of by a .APP file), it reads the alias information
and places this in a suitable position on the command line used to
start the application.

Note: an ALS file can also be created using the "Create new list"
menu option in the Series3a system screen.

See the first two chapters of the "Series 3/3a programming guide" in
volume 1 of the SiboSDK for more information about aliasing and
command lines in general.

Alias info for the text editor
------------------------------

If the alias info is a null string, the text editor enters Word mode,
with multi-level outline facilities, styles and emphases, and so on.

Note that it is not unreasonable for an alias to define null alias
info.  This allows the creation of aliases of the text editor that
behave in exactly the same way as the built-in Word application, but
differ from each other in terms of their default extensions, default
directories, and/or public names.

If there is any non-null alias info, the text editor enters one of a
number of other modes, with the mode depending on the first character
of the alias info.  Some of these modes are not available on Series 3
machines. At the time of writing, the allowed first characters and
the corresponding modes are:
  O     OPL program editor
  S     Comms script program editor
  $     Plain text editor (not Series 3)
  /     Word processor with custom template (not Series 3)

The program editor mode is available on all machines.  In this mode
there is no access to the style and emphasis subsystems, the
corresponding menu commands being replaced by options to "translate",
"run", "show error" and set "indentation".

In this mode, the first letter of the alias info denotes the nature of
the program that is being edited. It actually identifies the program
to invoke to effect any "translate" and (possibly) "run" commands
from the user.  The generic name of this program is sys$prg?.img,
with the question mark being filled in from the first letter of the
alias info.  Thus the Prog alias has 'O' for the first letter of its
alias info, and so the OPL translate/run program sys$prgo.img is
used. In contrast, the Script editor from the communications ROM has
'S' for the first letter of the alias info, so that the program 
sys$prgs.img is used.

In fact, there is no built-in restriction to the letters 'O' and 'S'
for the program editor.  Any alphabetic first letter of alias info
will place the text editor into program editing mode.

In program editor mode the second letter of the alias info should be
'R' if the program is of a type that understands "run" instructions
in addition to "translate" ones.  Any other second character disables
the "run" command option.  The following three letters (e.g. 'OPO' or
'SCO') denote both the expected file extension and the expected
top-level directory where any translated output will by default be
placed.  (This information is used by the editor when offering the
user a suitable filename to "run").

On the Series 3a a final '*' character may be added to the alias info.
This has the effect of adding an "S3 Translate" menu option.

The remaining modes are not available on Series 3 machines.

Alias info that consists of a single '$' character selects a plain
text editing mode. In this case the program-related menu options are
suppressed, with only an "indentation" option being offered.

A variant on the Word mode is set by alias info that consists of a
single '/' character.  This behaves in a similar way to the Word
application, with the exception that a specific template file is
loaded whenever a new file is created.  The template must have the
same name as the aliased application and must be located on the
current drive at the time the new file is created.

Thus, an alias created from the following .ma file:
  Letter.LET
  \LET\
  1083
  Word
  /                                                       

would, on creation of a new file, automatically load the template file
\wdr\letter.wrt, provided it exists on the current drive.  Note that,
in this mode, the value 80 must be added into the application type
number. If it is not, the automatic loading of the template is
disabled.