Visual M and MWAPI
Allison Leech
MWAPI?
thanks ;-) allison
The Children's Hospital - Denver
Daniel P. B. Smith
From the FAQ:
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11. Does M support Microsoft Windows and other GUIUs?
A 1994 addition to the M standard, the M Windowing API (MWAPI), defines an
interface between the M language and windowing systems.
InterSystems and Micronetics offer versions of M that implement the MWAPI in
a Microsoft Windows environment. Digital has an implementation [is it
commercially released? Details?] for Windows NT.
The M Windowing API and its commercial implementations are relatively new
and have rough edges. The MWAPI has the advantage of portability and
platform-independence, but has some limitations associated with the "least-
common-denominator" approach.
A unique feature of the MWAPI is that this "API" does not consist of
subroutine calls (except for a few incidental functions). MWAPI programming
consists mainly of performing sets and kills into a "structured system
variable," which looks like a standard M global. For example, to set the
title of a window to "M Technology Demonstration," you write
s ^$WINDOW("main","TITLE")="M Technology Demonstration"
To make its dimensions 300 by 200, you write
s ^$WINDOW("main","SIZE")="300,200"
The MWAPI is currently offered for Microsoft Windows by InterSystems and
Micronetics, and for Windows NT by Digital Equipment Corporation. It is
often presented as the windowing future for M technology.
VISUAL-BASIC-LIKE APPROACHES
InterSystems' "Visual M" is a set of tools which link M with Microsoft
Visual Basic, creating an integrated dual-language environment. M code can
be accessed and edited from within the VB design environment, can access VB
control properties, and can be triggered by VB events.
Micronetics [product name????] provides a Visual-Basic-like environment
entirely based on M and the MWAPI.
"WRITE-SLASH" APPROACHES
InterSystems' "DT-Windows," MGlobal's MGM-PC (for MS-Windows) and MGM-Mac
(for the Macintosh) use a feature of the M standard that allows the language
to be extended for device-specific purposes by means of the "write-slash"
syntax. In DT-Windows and MGM, the windowing system is treated as a
"device" with an unusually rich repertoire of device-specific commands.
Although DT-Windows and MGM are conceptually similar, they are incompatible
with each other. They are ad-hoc language extensions. Neither seems to
have set a defacto standard. Why do these products (DT-Windows and MGM)
provide a nonstandard approach? The answer, in part, is that they were
introduced prior to the finalization of the MWAPI standard. Why do they
still exist? Because they are closer to their underlying windowing platform
than the MWAPI, they arguably provide better performance and broader access
to the GUI system's functionality.
Examples from the DT-Windows manual and MGM product literature,
respectively, show how an "OK" button is added to a dialog box:
DT-Windows
w /waddbutton(2,65,40,10,20,1,1,1,0,0,0,"OK",1)
MGM
W /DBUTTON("OK",2,9)
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--
Daniel P. B. Smith
dpbs...@world.std.com
Paul Perrin
It would seem that the FAQ has a fairly low opinion of Write-Slash - and
maybe in respect of M 'the system' this is justified.
However, as far as practical use goes I find the write-slash format
very useful for mumps integration within the MSWindows enviroment.
Enabling data from a Mumps system (maybe from a ddp link to another
hardware platform) to be placed on the windows clipboard for pasting in
to other applications is invaluable.
I've recently been using this mechanism to allow editing of DTM code
using a windows based programmers editor (tho' I'm still experimenting)
From Memory:-
R "Routine Name:",ROUT W !
I ROUT="" Q
S SOURCE=$ZRS(ROUT)
I SOURCE="" Q
O 40 U 40 W /WSETCLIP(SOURCE)
; Prog can now paste code into windows editor
; Edit source
; Copy modified code back to clipboard
W "Hit <space> to reload source" R *X
I X'=$A(" ") Q
; Request Clipped Data, Get Response Message, If not null zsave
W /WGETCLIP
F I=1:1:10 W /WGETMESSAGE(.X) Q:X'="" H .5
I X="" Q
S SOURCE=$P(X,$C(22),5)
ZS @ROUT:SOURCE:1
Q
Probably the shortest program editor I've ever written :-).
Rgds
Paul Perrin /)/+)
r._gaudette
>Micronetics [product name????] provides a Visual-Basic-like environment
>entirely based on M and the MWAPI.
Product name is "MSM-View Builder"