* read-file-name() doesn't care about PREDICATE argument
@ 2010-03-17 11:49 Nordlöw
2010-03-17 14:24 ` Stefan Monnier
0 siblings, 1 reply; 3+ messages in thread
From: Nordlöw @ 2010-03-17 11:49 UTC (permalink / raw)
To: help-gnu-emacs
Why is the argument PREDICATE not used in read-file-name?
For example
(read-file-name "Find file: " "~/" nil t nil (lambda (filename)
nil))
incorrectly completes everything for me when it shouldn't complete
anything at all since the PREDICATE function always returns nil.
I have also tried the Icicles version
(icicle-read-file-name "Find file: " "~/" nil t nil (lambda
(filename) nil))
but it behaves exactly the same.
The following code works as expected, though:
(let ((icicle-must-pass-predicate (lambda (filename) nil)))
(icicle-read-file-name "Find file: " "~/" nil t nil (lambda
(filename) nil)))
Why doesn't first two example like the last? And why does the icicle
version provide this extra variable? It smells like a bug or a missing
feature.
/Nordlöw
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: read-file-name() doesn't care about PREDICATE argument
2010-03-17 11:49 read-file-name() doesn't care about PREDICATE argument Nordlöw
@ 2010-03-17 14:24 ` Stefan Monnier
2010-05-04 18:17 ` Drew Adams
0 siblings, 1 reply; 3+ messages in thread
From: Stefan Monnier @ 2010-03-17 14:24 UTC (permalink / raw)
To: help-gnu-emacs
> Why is the argument PREDICATE not used in read-file-name?
> For example
> (read-file-name "Find file: " "~/" nil t nil (lambda (filename) nil))
Maybe because you're still using Emacs-22?
This part of the code has been changed in Emacs-23, and in my tests it
seems to do what you want.
Stefan
PS: Note that this `predicate' argument is not handled quite right
currently, because it doesn't distinguish between "intermediate
completions to accept" and "final values to accept". So if you want to
be able to complete "/u" to "/usr/", then you need to accept "/usr/" as
a valid candidate, even though you only wanted to allow this completion
to let the user complete its way to a .pdf file somewhere underneath
/usr.
^ permalink raw reply [flat|nested] 3+ messages in thread
* RE: read-file-name() doesn't care about PREDICATE argument
2010-03-17 14:24 ` Stefan Monnier
@ 2010-05-04 18:17 ` Drew Adams
0 siblings, 0 replies; 3+ messages in thread
From: Drew Adams @ 2010-05-04 18:17 UTC (permalink / raw)
To: help-gnu-emacs
> > Why is the argument PREDICATE not used in read-file-name?
> > (read-file-name "Find file: " "~/" nil t nil
> > (lambda (filename) nil))
>
> Maybe because you're still using Emacs-22? This part of
> the code has been changed in Emacs-23, and in my tests it
> seems to do what you want.
(That example works in emacs -Q for Emacs 22 also - there are no possible
completions shown.)
> I have also tried the Icicles version
> (icicle-read-file-name "Find file: " "~/" nil t nil
> (lambda (filename) nil))
> but it behaves exactly the same.
It is intended to act the same as vanilla Emacs wrt PREDICATE.
Both should work (as opposed to neither working ;-)).
> The following code works as expected, though:
> (let ((icicle-must-pass-predicate (lambda (filename) nil)))
> (icicle-read-file-name "Find file: " "~/" nil t nil
> (lambda (filename) nil)))
>
> Why doesn't first two example like the last? And why does the icicle
> version provide this extra variable? It smells like a bug or a missing
> feature.
The Icicles variable `icicle-must-pass-predicate' is an _additional_ predicate.
It applies to any kind of completion. A similar but more specific variable
applies to only file-name completion: `icicle-file-predicate'.
These variables can be useful in programming. The latter is also a user option,
in case there is some general file-name filtering that someone always wants to
do. (There is a similar option for buffer names.)
The PREDICATE arg to `read-file-name' is available only for the code that
actually calls `read-file-name' (duh). If your code that wants to impose a
predicate calls existing code that calls `read-file-name' without a PREDICATE,
or if you interactively use an existing command that does that, then you have no
way to filter with your predicate.
That is, if the code that actually calls `read-file-name' did not forsee the
filtering you want, then you're out of luck.
That's the purpose of these Icicles variables: to let you do some global
filtering regardless of whatever filtering, if any, was provided by existing
code that calls `read-file-name' (or `completing-read'). Simply bind the
variable to the predicate you want. It will apply to completion calls within its
scope/extent.
http://www.emacswiki.org/emacs/Icicles_-_Global_Filters
^ permalink raw reply [flat|nested] 3+ messages in thread
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2010-03-17 11:49 read-file-name() doesn't care about PREDICATE argument Nordlöw
2010-03-17 14:24 ` Stefan Monnier
2010-05-04 18:17 ` Drew Adams
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