Completion and command versions

Completion and command versions

[Doug Kearns]

Is there a policy regarding the command version that completion
functions should support? What about commands where there are
significant changes between versions?

Any thoughts?

Thanks,
Doug

Re: Completion and command versions

[Peter Stephenson]

Doug Kearns wrote:
> Is there a policy regarding the command version that completion
> functions should support? What about commands where there are
> significant changes between versions?

The standard way is using the _pick_variant function.

If it's too dangerous to run the command to find out what it does, you
probably need a style.  `variant' is already use by _pick_variant,
unfortunately --- it's not a very good name, since it doesn't give the
variant, it gives the programme to run to pick the variant.  Of course
it could be set to a function that simply returns the type, but that
method doesn't have a sensible default.

-- 
Peter Stephenson <pws@csr.com>                  Software Engineer
CSR Ltd., Science Park, Milton Road,
Cambridge, CB4 0WH, UK                          Tel: +44 (0)1223 692070


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Re: Completion and command versions

[Oliver Kiddle]

Peter wrote:
> Doug Kearns wrote:
> > Is there a policy regarding the command version that completion
> > functions should support? What about commands where there are
> > significant changes between versions?

I don't think we have any official policy. For most commands, where the
differences are little more than a few added options I just update it
to the latest version.

If an option that takes an argument is removed you could precede the
_arguments spec with \! so that it is recognised but not completed.

Where a command changes significantly, and in particular where an old
version continues to be in wide use, it can then be worth the trouble
of handling the old version.

> The standard way is using the _pick_variant function.
> 
> If it's too dangerous to run the command to find out what it does, you
> probably need a style.  `variant' is already use by _pick_variant,
> unfortunately --- it's not a very good name, since it doesn't give the
> variant, it gives the programme to run to pick the variant.  Of course

_pick_variant is not in 4.0 so it isn't too late to change this. It
perhaps should stick with the command style but set the tag to `variant'
when looking it up.

Another issue we perhaps ought to think about is how we keep track
of what version of a command the functions have been updated to. I
notice some people have put a version number in a comment at the top
of functions which is one way. What we could do is setup a separate cvs
repository containing the output of the commands' --help (or equivalent)
outputs. I've found that diffing these is a good way of finding any
new options - assuming I still have the old program around to get it's
--help output.

Oliver

Re: Completion and command versions

[Oliver Kiddle]

On 14 Mar, Peter wrote:
> 
> The standard way is using the _pick_variant function.
> 
> If it's too dangerous to run the command to find out what it does, you
> probably need a style.  `variant' is already use by _pick_variant,
> unfortunately --- it's not a very good name, since it doesn't give the
> variant, it gives the programme to run to pick the variant.  Of course
> it could be set to a function that simply returns the type, but that
> method doesn't have a sensible default.

I just checked this again and _pick_variant doesn't use `variant' as a
style. It sets the tag name to `variant' when looking up the `command'
style. So the `variant' style is not already in use.

Oliver