[Info-vax] User Interface Design, Implementation (was: Re: link to what is actually being ported to x86?)

[Stephen Hoffman]

On 2019-06-03 23:09:21 +0000, Dave Froble said:

> I haven't looked at it, but WASD has, I believe, a browser based 
> terminal emulator.
> 
> I don't think my idea is popular, but, what I'd consider is a WEENDOZE 
> client that can be closely coupled with VMS apps.  The user interface 
> could be fed from the VMS app, or be a WEENDOZE GUI app which is part 
> of the overall app.

I'd avoid the closely-coupled UI approach, having made that mistake 
various times over the years.

Cleave an existing app and create a display API, and potentially also 
work to cleave the app in a few other spots depending on longer-term 
plans and goals.

The preferred client displays and UIs and platforms are going to vary 
over time, whether it was VWS and then X11, or command-line and then 
control sequences and terminals or terminal emulators, or REST via 
HTTPS, or some fully-bespoke network-connected client.

More often than not, two or three UIs can be in use at any one time, 
over the lifetime of a complex application.

Using this approach, an app might have ANSI control sequences via 
character cell, X11, VWS, and a command-line mode.  And can add remote 
access via network.

In various cases, the display API loads a callable shareable image for 
the particular interface, allowing the same app to support different 
schemes, and allowing the app to activate and operate even in the 
absence of display-specific dependencies.

Digging the display assumptions out of the code can run a gamut from 
easy to intractable.

In more recent times, this UI design and implementation discussion can 
be a subtopic of a larger app architectural discussion, such as 
model-view-controller app designs, or analogous schemes.

https://en.wikipedia.org/wiki/Model–view–controller

OpenVMS doesn't have a concept of MVC, though that's an approach that 
can certainly be used within OpenVMS apps.  And MVC has its issues.

The programming concepts and the modular procedures and the related 
"the VMS way" documentation are all in need of updates.  Including 
around topics relevant here such as UIs, networking, authentication, 
and encryption.

Alas, SMG and FMS and ANSI control sequences and such are very far from 
the pinnacle of what many folks expect for clients.


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