completion for printf-style format strings

completion for printf-style format strings

[Felix Rosencrantz]

Does anyone have code to perform completion of printf-style format strings?

I think it was suggested that it might be possible to do with 
_regex_arguments. but not sure if there is an example somewhere or a
utility function.

I'm not sure if such completion would help reduce typing, but being
able to get a context based listing of possible values could help skip
a trip to the documentation..

-FR.

Re: completion for printf-style format strings

[Oliver Kiddle]

Felix Rosencrantz wrote:
> Does anyone have code to perform completion of printf-style format strings?
> 
> I think it was suggested that it might be possible to do with 
> _regex_arguments. but not sure if there is an example somewhere or a
> utility function.

It wouldn't be possible with _regex_arguments. _regex_arguments is only
useful when completing a single command-line argument in full. It never
uses compset -P/-S to cut the current word down into chunks.

You would probably want to use patterns a lot though. Basically you need
to remove any literal characters and complete format specifications from
the front of the word. Then you can deal with any partially complete
format specifications. What might be good is to make it sufficiently
general so as to be usable for things like strftime too.

Oliver

Re: completion for printf-style format strings

[Felix Rosencrantz]

If _regex_arguments doesn't provide a means or even a good example.   
 Do you think that it would make sense to modify _regex_arguments to
add code that would cause it to use the  compset -P/-S flags?

The _regex_arguments function relies on zregexparse, which is not
really documented, though it does have a dedicated test suite.  Would
it make sense to try to decipher that and make it try to search for
just substrings of the current word? Is that possible.  Or do you
think this is more a task for compadd/compset?  Is there an existing
utility function that could be used/modified?

I was thinking maybe _values might be good to look at, instead of
using a hard-coded separator, maybe a regex could be used.  Though it
uses compvalues which is not documented or tested(!).

It would be very useful to be able to complete alot of different
format strings.  I think you mentioned strftime since it can have
multi-letter formats. I think there are a lot of useful places it
could be used, like zsh prompts or the builtin print command.  Also
things like the date command or the find -printf flag.

Again, I'm not sure that this would directly help with a reduction in
typing, but I think it would help reduce the need to visit the
documentation, which would be useful.

-FR.