[Haskell-cafe] cabal-install problem with alex dependency in bytestring-lexing

Erik de Castro Lopo mle+hs at mega-nerd.com
Fri Mar 16 11:56:41 CET 2012

Joachim Breitner wrote:

> no, cabal-install does not automatically install build-tools at all,
> only Cabal checks them for compilation. I guess the reason is that
> build-tools needs to be put on the PATH, and that is beyond the scope of
> cabal-install.

This is rather sub-optimal.

One place where people are running into this problem is when installing
Yesod. Yesod depends on warp which depends on bytestring-lexing which
requires alex at build time.

The problem is that many of the people trying out Yesod are newcomers to
Haskell. They are going to try  "cabal install yesod" and have it fail
because alex is missing. This is not a good introduction Haskell/Yesod.

Erik de Castro Lopo

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