问题安装快乐

我正在尝试安装Fay.Fay有依赖pretty-show,所以我正在安装它.当我运行时cabal install pretty-show,我收到以下错误:

Resolving dependencies...
Configuring pretty-show-1.6.2...
cabal: The program happy version >=1.19 is required but the version found at
/usr/bin/happy is version 1.18.10
Failed to install pretty-show-1.6.2
cabal: Error: some packages failed to install:
pretty-show-1.6.2 failed during the configure step. The exception was:
ExitFailure 1

当我试图跑步时cabal install happy,它表示它是成功的:

Resolving dependencies...
[1 of 1] Compiling Main             ( /var/folders/d1/h6lvlvnd0j18lf3ml2rn11dm0000gq/T/happy-1.19.2-89313/happy-1.19.2/Setup.lhs, /var/folders/d1/h6lvlvnd0j18lf3ml2rn11dm0000gq/T/happy-1.19.2-89313/happy-1.19.2/dist/setup/Main.o )
Linking /var/folders/d1/h6lvlvnd0j18lf3ml2rn11dm0000gq/T/happy-1.19.2-89313/happy-1.19.2/dist/setup/setup ...
Configuring happy-1.19.2...
Building happy-1.19.2...
Preprocessing executable 'happy' for happy-1.19.2...
[ 1 of 18] Compiling NameSet          ( src/NameSet.hs, dist/build/happy/happy-tmp/NameSet.o )
[ 2 of 18] Compiling Target           ( src/Target.lhs, dist/build/happy/happy-tmp/Target.o )
[ 3 of 18] Compiling AbsSyn           ( src/AbsSyn.lhs, dist/build/happy/happy-tmp/AbsSyn.o )
[ 4 of 18] Compiling ParamRules       ( src/ParamRules.hs, dist/build/happy/happy-tmp/ParamRules.o )
[ 5 of 18] Compiling GenUtils         ( src/GenUtils.lhs, dist/build/happy/happy-tmp/GenUtils.o )
[ 6 of 18] Compiling ParseMonad       ( src/ParseMonad.lhs, dist/build/happy/happy-tmp/ParseMonad.o )
[ 7 of 18] Compiling Lexer            ( src/Lexer.lhs, dist/build/happy/happy-tmp/Lexer.o )
[ 8 of 18] Compiling Parser           ( dist/build/happy/happy-tmp/Parser.hs, dist/build/happy/happy-tmp/Parser.o )
[ 9 of 18] Compiling AttrGrammar      ( src/AttrGrammar.lhs, dist/build/happy/happy-tmp/AttrGrammar.o )
[10 of 18] Compiling AttrGrammarParser ( dist/build/happy/happy-tmp/AttrGrammarParser.hs, dist/build/happy/happy-tmp/AttrGrammarParser.o )
[11 of 18] Compiling Grammar          ( src/Grammar.lhs, dist/build/happy/happy-tmp/Grammar.o )
[12 of 18] Compiling First            ( src/First.lhs, dist/build/happy/happy-tmp/First.o )
[13 of 18] Compiling LALR             ( src/LALR.lhs, dist/build/happy/happy-tmp/LALR.o )
[14 of 18] Compiling Paths_happy      ( dist/build/autogen/Paths_happy.hs, dist/build/happy/happy-tmp/Paths_happy.o )
[15 of 18] Compiling ProduceCode      ( src/ProduceCode.lhs, dist/build/happy/happy-tmp/ProduceCode.o )
[16 of 18] Compiling ProduceGLRCode   ( src/ProduceGLRCode.lhs, dist/build/happy/happy-tmp/ProduceGLRCode.o )
[17 of 18] Compiling Info             ( src/Info.lhs, dist/build/happy/happy-tmp/Info.o )
[18 of 18] Compiling Main             ( src/Main.lhs, dist/build/happy/happy-tmp/Main.o )
Linking dist/build/happy/happy ...
Warning: No documentation was generated as this package does not contain a
library. Perhaps you want to use the --executables flag.
Installing executable(s) in
/Users/buck2/Library/Haskell/ghc-7.6.3/lib/happy-1.19.2/bin
Installed happy-1.19.2
Updating documentation index /Users/buck2/Library/Haskell/doc/index.html

但是当我打电话时cabal info happy,它会说这个,我认为这意味着它没有安装:

Bucks-MacBook-Pro:~ buck2$ cabal info happy
* happy            (program)
    Synopsis:      Happy is a parser generator for Haskell
    Versions available: 1.16, 1.17, 1.18.8, 1.18.9, 1.18.10, 1.18.11, 1.19.0,
                        1.19.1, 1.19.2 (and 7 others)
    Versions installed: [ Unknown ]
    Homepage:      http://www.haskell.org/happy/
    Bug reports:   https://github.com/simonmar/happy/issues
    Description:   Happy is a parser generator for Haskell. Given a grammar
                   specification in BNF, Happy generates Haskell code to parse
                   the grammar. Happy works in a similar way to the @yacc@ tool
                   for C.
    Category:      Development
    License:       BSD3
    Author:        Andy Gill and Simon Marlow
    Maintainer:    Simon Marlow 
    Source repo:   http://github.com/simonmar/happy.git
    Executables:   happy
    Flags:         small_base
    Dependencies:  base >=1.0 && <2.1, containers -any, array -any, base >=2.1,
                   mtl >=1.0, base <5, process -any, base -any
    Cached:        Yes

任何想法为什么我会得到这个问题？我正在运行OS X Mavericks,我今天刚刚重新安装了Haskell平台.