问题
I'm trying to install the lens package to work with haskell.
$ haste-inst install lens
I get the following error:
Resolving dependencies...
cabal: Could not resolve dependencies:
trying: base-4.6.0.1/installed-4.6... (user goal)
trying: containers-0.4.1.0/installed- (user goal)
trying: lens-4.9.1 (user goal)
next goal: template-haskell (dependency of lens-4.9.1)
rejecting: template-haskell-2.10.0.0 (conflict:
base==4.6.0.1/installed-4.6..., template-haskell => base==4.8.*)
rejecting: template-haskell-2.9.0.0 (conflict: base==4.6.0.1/installed-4.6...,
template-haskell => base==4.7.*)
rejecting: template-haskell-2.8.0.0 (conflict: containers==0.4.1.0/installed-,
template-haskell => containers==0.5.*)
rejecting: template-haskell-2.7.0.0 (conflict: base==4.6.0.1/installed-4.6...,
template-haskell => base==4.5.*)
rejecting: template-haskell-2.6.0.0 (conflict: base==4.6.0.1/installed-4.6...,
template-haskell => base==4.4.*)
rejecting: template-haskell-2.5.0.0 (conflict: base==4.6.0.1/installed-4.6...,
template-haskell => base==4.3.*)
rejecting: template-haskell-2.4.0.1 (conflict: base==4.6.0.1/installed-4.6...,
template-haskell => base==4.2.*)
rejecting: template-haskell-2.4.0.0 (conflict: base==4.6.0.1/installed-4.6...,
template-haskell => base>=3 && <4.3)
rejecting: template-haskell-2.3.0.1, 2.3.0.0, 2.2.0.0 (conflict: lens =>
template-haskell>=2.4 && <2.11)
Backjump limit reached (change with --max-backjumps).
Note: when using a sandbox, all packages are required to have consistent
dependencies. Try reinstalling/unregistering the offending packages or
recreating the sandbox.
I believe the sandbox "Note" to be misleading. The sandbox is new and base cannot exist in the sandbox anyway.
What determines the version of base for haste? Installing lens with cabal (for haskell) works fine:
cabal install lens
Edit:
lens-family has worked well as a substitute so far.
回答1:
Lens depends on Template Haskell which, unfortunately, is not currently supported by Haste.
The way base is currently implemented for Haste makes TH support tricky. However, GHC 7.10 support will require some significant reshuffling anyway, so TH support will probably arrive together with 7.10.
来源：https://stackoverflow.com/questions/29832702/cannot-install-lens-with-haste-inst