Re: Generalizing find-definition

[Stephen Leake]

Stefan Monnier <address@hidden> writes:

> > from foo import Foo

> > bar = Foo()
> > bar.baz_|_

>> The only single string that reliably would allow to find the correct
>> definition would be "foo.Foo.baz", but I do not think that anyone
>> would consider that to be "the identifier at point" here.
>
> I would.

I would also, but I would not expect a generic Emacs function to return
that. It certainly requires a backend function.

I'm still not clear what 'identifier-at-point' is good for outside "goto
definition", "show uses", and completion. Since the meaning is highly
backend specific, I don't see what other parts of Emacs might use it.

You say there are other uses - can you list some?

In ada-mode, 'ada-identifier-at-point' is used in (ada-mode doesn't
provide completion yet):

ada-goto-declaration

    aka find-definition-function
    
ada-show-references

    aka find-uses-function
    
ada-show-declaration-parents

    If identifier-at-point is a type, show the definition of the types
    it inherits from.
    
ada-show-overriding

    If identifier-at-point is a function, show definitions
    of functions that override it.
    
ada-show-overridden

    If identifier-at-point is a function, show definitions
    of the function that it overrides.

The last three are additional candidates for the API.

>>> Note that such completion tables are clearly not lists of strings, but
>>> they're functions (actually, they're objects represented as functions,
>>> for lack of an object system).
>> What is the advantage of having the backend define a function that
>> returns a completion table as opposed to a function that prompts the
>> user for a symbol? The saved code seems minimal, and it means the
>> backend can not set the prompt, for example.
>
> It means the UI can use it for various kinds of completion (e.g. for
> completion-at-point-function).

+1

ada-mode would provide a tree as well.

-- 
-- Stephe