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Re: [Texmacs-dev] Interactive feedback
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From: |
David Allouche |
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Subject: |
Re: [Texmacs-dev] Interactive feedback |
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Date: |
Wed, 25 Feb 2004 15:44:04 +0100 |
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User-agent: |
Mutt/1.5.5.1+cvs20040105i |
Nice feedback, I really appreciate it.
On Wed, Feb 25, 2004 at 11:48:26AM +0100, Joris van der Hoeven wrote:
> (let-interactive ((x "First argument")
> (y "Second argument"))
> prg)
>
> which should return nothing when executing, but which passes
> control to the status bar (or a popup widget) and asks for
> user feedback. Moreover, we keep the "prg" continuation,
> which is executed when the user is done (except when
> the user cancels).
If I understand correctly, this should already be feasible using the
current improved implementation of "interactive", and without actually
using Scheme continuation, though it is reminiscent of the "continuation
passing style".
(let-interactive ((x "First")) <body>)
==>
(interactive '("First") (lambda (x) <body>))
Something like (just proof of concept, more syntax checking would be
needed):
(define-macro (let-interactive prompts . body)
`(interactive (quote ,(map second prompts))
(lambda ,(map first prompts) ,@body)))
Continuations are essentially a mechanism for non-local exit, there is
no need for non-local exit here, so no need for continuations.
> The current way of handling interactive commands can
> also easily be simulated.
I'd rather take it the other way around. What you propose can be easily
implemented on top of the improved "interactive" primitive.
> It might be a good idea to implement user feedback from
> popup windows all along with this. Also, the idea may
> be further extended so as to allow things like
>
> (let-interactive
> ((name "File name" url)
> (operation "Operation" (enum "Blah" "Hop"))
> (confirm? "Really do this" bool))
> prg)
>
> and to generate an appropriate widget or footer feedback.
That is a whole different can of worms. A KISS system to build dialog
windows would indeed be a good thing, but I do not really feel like
digging in the texmacs toolkit code to do that. I'd really rather just
tear the whole thing down and put another toolkit in there.
On a more incremental perspective, it would be a good thing to provide
support for tab-completion in the footer. I think the right way would be
something like:
(interactive `(("Prompt" ,tab-complete-prompt)) proc)
Where tab-complete-prompt would be "string -> (list string)" and return
a list of possible completions for the current prompt. Tab completion
would only be enabled when the caret is at the end of the footer input
text.
Probably something more elaborate would be nice to provide zsh-style
tab-completion, but this interface might be enough for bash-style
completion. Actually looking at the interface for defining
tab-completions in zsh, bash or emacs would also be a good thing, since
it would save us the trouble of reinventing this wheel.
> Delayed commands might be implemented in a similar way too.
What are you thinking about? As far as I understand delayed commands, it
is just a mechanism to postpone the execution of a procedure until the
next time the main event loop is run.
Generally, since continuations implement the same interface as
procedures, any higher-level procedure (which accepts a procedure as
a parameter) can work with continuations, or continuations wrapped in
closures so they accept the right number of arguments. Anything more is
just syntactic sugar.
--
-- ddaa