Re: [Haskell-cafe] Inject cabal version or VCS version as a CPP macro

22 Feb 2012


      Eugene Kirpichov  writes:
...
It can be used like this:
{-# LANGUAGE TemplateHaskell #-}
 import Distribution.VcsRevision.Git
 import Language.Haskell.TH.Syntax
showMyGitVersion :: String
 showMyGitVersion = $(do
   v <- qRunIO getRevision
   lift $ case v of
     Nothing           -> "<none>"
     Just (hash,True)  -> hash ++ " (with local modifications)"
     Just (hash,False) -> hash)
Btw, I'm wondering (haven't tried myself), when using TH to generate the
version string, does GHC's and/or cabal's dependency tracking

 a) reliably refresh the generated hash so that you can be sure it's
    the git-commit id compiled into the binary is reliable, and

 b) avoid re-generating the TH file and redundant recompilation if the
    git commit-id hasn't changed?

hvr
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Re: [Haskell-cafe] Inject cabal version or VCS version as a CPP macro

Herbert Valerio Riedel