Wednesday, November 19, 2014

Announcing Shake 0.14

Summary: Shake 0.14 is now out. The *> operator became %>. If you are on Windows the FilePath operations work differently.

I'm pleased to announce Shake 0.14, which has one set of incompatible changes, one set of deprecations and some new features.

The *> operator and friends are now deprecated

The *> operator has been the Shake operator for many years, but in GHC 7.10 the *> operator is exported by the Prelude, so causes name clashes. To fix that, I've added %> as an alias for *>. I expect to export *> for the foreseeable future, but you should use %> going forward, and will likely have to switch with GHC 7.10. All the Shake documentation has been updated. The &*> and |*> operators have been renamed &%> and |%> to remain consistent.

Development.Shake.FilePath now exports System.FilePath

Previously the module Development.Shake.FilePath mostly exported System.FilePath.Posix (even on Windows), along with some additional functions, but modified normalise to remove /../ and made </> always call normalise. The reason is that if you pass non-normalised FilePath values to need Shake can end up with two names for one on-disk file and everything goes wrong, so it tried to avoid creating non-normalised paths.

As of 0.14 I now fully normalise the values inside need, so there is no requirement for the arguments to need to be normalised already. This change allows the simplification of directly exporting System.FilePath and only adding to it. If you are not using Windows, the changes are:

  • normalise doesn't eliminate /../, but normaliseEx does.
  • </> no longer calls normalise. It turned out calling normalise is pretty harmful for FilePattern values, which leads to fairly easy-to-make but hard-to-debug issues.

If you are using Windows, you'll notice all the operations now use \ instead of /, and properly cope with Windows-specific aspects like drives. The function toStandard (convert all separators to /) might be required in a few places. The reasons for this change are discussed in bug #193.

New features

This release has lots of new features since 0.13. You can see a complete list in the change log, but the most user-visible ones are:

  • Add getConfigKeys to Development.Shake.Config.
  • Add withTempFile and withTempDir for the Action monad.
  • Add -j to run with one thread per processor.
  • Make |%> matching with simple files much faster.
  • Use far less threads, with corresponding less stack usage.
  • Add copyFileChanged.


I'm hoping the next release will be 1.0!

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