Re: Generation of tags for the current project on the fly

[Dmitry Gutov]

On 1/17/18 23:12, Eli Zaretskii wrote:

> > > > The information is inside the TAGS file, isn't it?
> > >
> > > Not really: the signature of each file at the moment of scan is
> > > missing, and maybe also other things.
> >
> > Meaning it's not known at etags runtime? That's true.
>
> It's also not recorded after the run, so that the next run could
> compare against it.

What's a signature? The file names are recorded, of course. But not 
mtimes, if you mean them.

> > Make tracks which files need to be recompiled, right? This could reuse
> > the same mechanism, if possible.
>
> Make doesn't support incremental builds, except on file granularity.
> Doing that with etags would be easy, but you say that is not the
> "incremental" tagging you had in mind, you want the granularity to be
> below file, i.e. on tag level.  For that, a single time stamp of the
> TAGS file is insufficient, because all it can tell you is which files
> need to be re-tagged, whereas you want to know that on a per-tag
> basis.

On the contrary: file granularity should be fine. We just need *some* 
accounting somewhere to detect which files to reindex.

It's hard for me to imagine how a granularity lower than file would even 
work.

Another question is how to deal with file deletions: when a file is 
absent, there's nothing to take into account, for Make to trigger an 
incremental rebuild (or actually a deletion of this file's entry). Maybe 
this is a rare enough case, though, that 'make tags' users will deal 
with it manually in some fashion or other.