Feature request: Generate tags for dependent haskell packages

[jsynacek]

It would be nice to have an option (maybe not enabled by default) to also generate tags for the dependent packages specified in the cabal file, including base. There is a project that does something similar, see https://github.com/ierton/haskdogs.

[jimenezrick]

Yeah, something like this: https://github.com/aloiscochard/codex
Which you can use to index all dependent packages very easily.

[arybczak]

Oh, I didn't know about codex. Wouldn't it be better to add support of ghc-tags to codex though, considering it can already handle both hasktags and ctags?

[jimenezrick]

ghc-tags looks feature rich and tightly integrated with GHC, which i think is great, my personal preference would be to enhance ghc-tags to be more cabal/project aware and locate all the source files all of the packages to index, but that's just me preference.

The support inside codex would be more ad-hoc, but again, just my 2c.

[jimenezrick]

I was having a look how codex does it, and cabal downloads all the source files used for build under ~/.cabal/packages/hackage.haskell.org, the problem is, it ends up in there as tarballs. Seems like codex identifies the dependent packages and unpack them: https://github.com/aloiscochard/codex/blob/6edbdc34357d13e52b434c19665725684cdd2dba/src/Codex.hs#L148

If we would get all the tarballs unpacked (we could use a bash script), we could run ghc-tags recursively under ~/.cabal/packages/hackage.haskell.org directly as i saw:

  source_paths - a list of paths for ghc-tags to process. Directories are traversed recursively.

Just thinking that with a simple script, ghc-tags can run directly there and give you some tags out of the box as it is now :)

[jimenezrick]

I was playing doing some plumbing with these tools:

• cabal-plan: to show the exact dependencies of the current project
• poor man's script (bash): to unpack those dependencies source tarballs from ~/.cabal/packages/hackage.haskell.org
• ghc-tags: to index all those folders

...and success :)

[jimenezrick]

Just for awareness, i ended up writing a small tool for this:
https://github.com/jimenezrick/cabal-project-tags