Accessing the package version from within the package

[basvandijk]

Just like you can access data files from a package, it would be useful to retrieve the current version of your package from within your program.

This is useful when you want to print the current version of your program when the user issues a --version flag for example.

More specifically I would like the following module to be generated automatically:

module Version_pkgname where

import Distribution.Version (Version)

version :: Version
version = <the current package version>

where Version is from the Cabal library.

Having just a String for the version type is also OK and maybe even preferable because otherwise a dependency on the Cabal library is required.

[AntoineLatter]

Maybe I'm miss-understanding, but this feature already exists exactly as you've described.

Paths_$pkgname.version :: Version

is exported by default.

I'm not sure in which version it was introduced, and the user guide makes no mention of the feature.

Here's the code in 1.10:

 http://www.haskell.org/ghc/docs/7.0.2/html/libraries/Cabal-1.10.1.0/src/Distribution-Simple-Build-PathsModule.html

[basvandijk]

Replying to AntoineLatter:

Maybe I'm miss-understanding, but this feature already exists exactly as you've described.

Indeed. I just discovered this myself when browsing through the autogen directory of one of my packages and reading the Paths_package module.

I'm closing the ticket as worksforme.

[basvandijk]

I wrote some documentation.