[BRLTTY] Feature request: configurable prompt pattern

[Dave Mielke]

[quoted lines by Aura Kelloniemi on 2018/03/15 at 08:26 +0200]

>I'm very sorry if I made an offense. I said, "a bit of a hack", and I consider
>my own proposal to be such too. 

I don't personally take offense to much, including this issue. To me, though, 
the term "hack" means carelessly thrown together without much, if any, 
forethought. I disagree that the current paradigm is anywhere close to that.

I've already mentioned that it made little sense to move to a prompt when the 
screen isn't reasonably stable, which is the case while a command is still 
running. Now that we have Track Screen Scroll, however, it does make sense. 
Since the Track Screen Scroll feature is new in 5.6, so just a little over a 
month old, claiming that a rather old feature which isn't all that useful 
without the new feature is a "hack" is, at least to me, rather unfair.

I forget how old NX/PRPROMPT is, but they go back quite a way. Until not all 
that long ago, we had an unofficial requirement to stay away from too many 
dependencies because brltty had to be able to be squeezed onto a boot disk. 
While this is no longer true, again, something not being enhanced just because 
the thought of revisiting it hasn't yet come up doesn't make its current 
implementation a "hack".

So, please, let's stay away from making judgements. They simply aren't 
necessary, don't add anything useful to any discussion, and, more often than 
not, rghtly or wrngly, they come off as self exultation. I don't like it, and 
will push back against it.

>There is no perfect solution, because TTY is not a system which can carry 
>metadata about semantics of applications.

Sure. Another such issue, which impacts brltty's linear copy feature, is when 
the end of a line within a multi-line copy isn't blank. Is it, or isn't it, 
line continuation (wrapping). It's impossible to know without a bit of human 
judgement. Of course we could add tons of code to try to get it right, but 
would all that complexity justify such little gain?

>I don't know what is good for others, nor do I pretend to. 

Yes, so let's please choose a way of expressing ourselves that assumes 
usefulness to others.

>I particularly like applications which can be scripted. 

That's yet another, entirely separate, potentially useful feature. We can 
discuss that, too. I'm not sure how much bloat and inefficiency it might add to 
brltty, but, as with anything else, we won't know until we discuss it. Do you 
have any particular scripting language and/or approach in mind?

>If this ability was available in BRLTTY, I would have scripted my own movement 
>commands long time ago. 

But, then, the idea of providing more powerful functionality within brltty 
itself may never have come up. You may be interpreting my challenging your 
choice of words and my questioning of your ideas as resistence, but you'd be 
wrong. Your idea is good. A few days worth of my challenges are just because I 
want to get it right rather than implement a "hack".

>The only kind of benefit from this approach would be that then the
>context-sensitive and the context-insensitive behaviour would be both
>available at the same time, if somebody wants them. 

That may not be true. I can think of a way to do it and am wondering what you 
think about it.

We could allow several patterns to be specified. For example:

   prompt-pattern pattern1
   prompt-pattern pattern2
   prompt-pattern pattern3

We could then check the current line to see if it matches any of them. If it 
does then we do the context-dependent thing with just that pattern, and, if it 
doesn't, then we join them, e.g.:

   (pattern1|pattern2|pattern3)

and do the context-independent thing. We could even also have command modifiers 
that could be added within the key table (like how +on and +off work for toggle 
commands) to force it one way or the other.

-- 
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