Re: space, M-x

[Stefan Monnier]

> I am a proponent of tab-completion and history, whenever the user enters
> a non-trivial command.  In order to improve the `M-x' behaviour, Emacs
> can use whitespace as delimeter. For example:

>  M-x set-fill-column M-space 80 RET

This may be marginally more convenient than "C-8 0 M-x set-fill-column
RET" in some cases, indeed (basically in the cases where you've started
M-x before realizing you needed to pass a prefix arg).

> should translate to (set-fill-column 80).  Since this is a command, not
> merely a function, we can also use the arguments to `interactive' as a
> way to do completion for the arguments of the command. For example:

>  M-x make-directory M-space ~/<TAB>

But I don't see what's the point of this one.

   M-x make-directory RET ~/<TAB>

works just as well, doesn't it?

> Obviously there are implementation issues. For instance how to handle
> `forms' as argument to `interactive', as that is much harder than
> handling something like (interactive "f"). But I think this worth
> trying. What do you think?

There is probably something worthwhile to find down this road, but
I think we need to first think harder about which cases coulod beneift
from something like that.
As you say, the implementation might be an issue (and in the form you
suggest above, it's really unclear what the implementation should/could
be), so we'd first need to have a clear idea of what are the important
cases to handle.

As easy thing to do would be to provide a new binding in the M-x
completion that takes a prefix arg, exits from the minibuffer and passes
the prefix arg to the specified command.  But that would only work for
a prefix arg.


        Stefan