Re: Emacs contributions, C and Lisp

[Óscar Fuentes]

David Kastrup <address@hidden> writes:

[snip]

>> We already have elaborate infrastructure for this kind of features:
>> CEDET and in particular Semantic.  Moreover, we included CEDET in
>> Emacs several releases ago precisely _because_ we wanted to move in
>> the direction of making Emacs a better IDE.  If we need more of what
>> is in ECB and the upstream CEDET, we can bring that in.  This is IMO
>> the preferred direction: make Emacs features depend on nothing but
>> Emacs packages.

I know that you don't trust me when I say that this is foolish, so I'll
recommend to you to ask on gcc-devel: "how much work it is to implement
the necessary features from scratch (say on Elisp) for providing C++
smart code completion as Clang does?"

You can also take a look at GCC or Clang sources to get an idea of the
involved complexity (not that the sources reflects all the complexity.)

[snip]

> We have the statement here (and far too little attention has been paid
> to it) that -fdump-xref and associated programs of the GNAT project
> would do the trick for the editing task currently at issue.  So there is
> a prototype people could be testing and experimenting with instead of
> doing flame wars.

You can see -fdump-xref as adequate only if you look at it with the
Etags mindset. -fdump-xref does not solve this most common pattern where
you type this two lines in sequence:

auto x = <some-expression>;
x. <- request code completion here

You need to figure out the type of `x' for providing the completion
candidates on the second line. For that, you'll need to start by
rebuilding and reading the output of -fdump-xref for the current compile
unit, which is very resource-intensive. Also, -fdump-xref would need to
work well enough on malformed source code.

[snip]