How can I use GHCi with the new cabal 1.17 sandboxes?

Question

I've been trying out cabal head which has support for sandboxes similar to cabal-dev. However there's not yet support for a cabal-dev ghci equivalent and apparently no support planned for the next release.

Is there some incantation I can use to work around this and get something similar to cabal-dev ghci?

Answer 1

edit (August 2013): The cabal repl patches have recently been merged. This functionality will be a part of the next release.

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As of this writing, there is no easy-to-use analogue to cabal-dev ghci. We plan to add a cabal repl command in the future - however, at the moment this functionality is not in Cabal HEAD.

In the meantime, you can try the following workaround:

$ cd $YOUR_PACKAGE_DIR  # For GHC >= 7.6 $ ghci -no-user-package-db -package-db .cabal-sandbox/i386-linux-ghc-7.6.1-packages.conf.d  # For GHC < 7.6 $ ghci -no-user-package-conf -package-conf .cabal-sandbox/i386-linux-ghc-7.4.2-packages.conf.d 

This won't make the modules of your package immediately available from ghci - you will have to load them with :l or import (which can break in the presence of custom preprocessors and CPP).