RE: IDE

[Drew Adams <drew.adams@oracle.com>]

> > Sounds like good ol' Emacs TAGS, to me (or across-project Imenu).
> > Of course, the limiting factor is TAGS files that support such
> > "things".  But the infrastructure is there for it.  People have
> > been using Emacs TAGS files to "jump to the [definition of the]
> > thing at point" for 40 years.
> 
> btw, recent GNU GLOBAL has now shifted to using a SQLite database for
> its tags files, which makes it hugely more extensible, in theory, and
> also makes it possible that Emacs could (once the modules code lands so
> we could write a glue layer to SQLite) directly extract info from it.
> 
> Raw TAGS files are more or less unsuitable for anything but C and Lisp,
> and are pretty poor even for that (e.g. you can only jump from uses to
> definitions, the definition can only be in one place...)

I don't think this is something inherent in TAGS files.

You can write a TAGS file for any kind of "definitions".
And I put that in quotes because such a "definition" can
really mean anything at all.  A TAGS file is just an index
into a document or a set of documents.

The fact that a program might not exist yet for creating
useful TAGS files for some language does not change this.

And the same thing you say about TAGS could be said about,
say, Imenu:  Until/unless someone writes the code needed
to use Imenu in a particular mode, it does not support that
mode.  That's not a problem with or limitation of Imenu.
It's just a lack of interest in writing the requisite
support for it for that mode/language.

It's also not clear to me what you mean by "the definition
can only be in one place".  AFAIK, you can have multiple
definitions of ("defining" locations for) the same thingy
in a single TAGS file.

And certainly you can have multiple such in a _set_ of
TAGS files.  And part of the use of TAGS files is
searching across multiple TAGS files.  TAGS files are
composable: they can be used together.

Please correct me if I'm mistaken.  I'm no expert on
TAGS files.

(Also, it is welcome that SQLite and other indexing and
querying means also be made available to Emacs.  Emacs
is not limited to TAGS or Imenu or ...  Tomorrow you
might use a SQL database with SQL/JSON indexing and
querying.  Who knows?)