Mac OS X 上的安装haskell开发环境

到haskell官方下载haskell的工具包：
https://downloads.haskell.org/~platform/2014.2.0.0/Haskell%20Platform%202014.2.0.0%2064bit.signed.pkg

adeMacBook-Pro:haskell_dev apple$ ghci
GHCi, version 7.8.3: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
Prelude> putStrLn "Hello World"
Hello World
Prelude>

参考文档：
http://rwh.readthedocs.org/en/latest/chp/1.html
解析：

把下面这段代码保存成SimpleJSON.hs

-- file: ch05/SimpleJSON.hs
data JValue = JString String
| JNumber Double
| JBool Bool
| JNull
| JObject [(String, JValue)]
| JArray [JValue]
deriving (Eq, Ord, Show)

-- file: ch05/SimpleJSON.hs
getString :: JValue -> Maybe String
getString (JString s) = Just s
getString _ = Nothing

-- file: ch05/SimpleJSON.hs
getInt (JNumber n) = Just (truncate n)
getInt _ = Nothing

getDouble (JNumber n) = Just n
getDouble _ = Nothing

getBool (JBool b) = Just b
getBool _ = Nothing

getObject (JObject o) = Just o
getObject _ = Nothing

getArray (JArray a) = Just a
getArray _ = Nothing

isNull v = v == JNull

main = print (JObject [("foo", JNumber 1), ("bar", JBool False)])

然后在ghci中把add.hs加载进去就可以了：

adeMacBook-Pro:haskell_dev apple$ ghci

GHCi, version 7.8.3: http://www.haskell.org/ghc/ :? for help

Loading package ghc-prim ... linking ... done.

Loading package integer-gmp ... linking ... done.

Loading package base ... linking ... done.

Prelude> :load SimpleJSON.hs

[1 of 1] Compiling Main ( SimpleJSON.hs, interpreted )

Ok, modules loaded: Main.

*Main> getString (JString "hello")

Just "hello"

*Main> getString (JNumber 3)

Nothing

*Main> getString (JString "hello")

Just "hello"

*Main>

编译haskell

adeMacBook-Pro:haskell_dev apple$ ls

Assign.hs InteractWith.hi SimpleJSON.hs WC.o myDrop.hs

BookStore.hs InteractWith.hs WC add.hs quux.txt

HelloWorld.hs InteractWith.o WC.hi hello-in.txt upperCase.hs

InteractWith Maybe WC.hs hello-out.txt

adeMacBook-Pro:haskell_dev apple$ ghc SimpleJSON.hs

[1 of 1] Compiling Main ( SimpleJSON.hs, SimpleJSON.o )

Linking SimpleJSON ...

adeMacBook-Pro:haskell_dev apple$ ls

Assign.hs InteractWith.hs SimpleJSON.hs WC.o quux.txt

BookStore.hs InteractWith.o SimpleJSON.o add.hs upperCase.hs

HelloWorld.hs Maybe WC hello-in.txt

InteractWith SimpleJSON WC.hi hello-out.txt

InteractWith.hi SimpleJSON.hi WC.hs myDrop.hs

adeMacBook-Pro:haskell_dev apple$ ls

Assign.hs InteractWith.hs SimpleJSON.hs WC.o quux.txt

BookStore.hs InteractWith.o SimpleJSON.o add.hs upperCase.hs

HelloWorld.hs Maybe WC hello-in.txt

InteractWith SimpleJSON WC.hi hello-out.txt

InteractWith.hi SimpleJSON.hi WC.hs myDrop.hs

adeMacBook-Pro:haskell_dev apple$ ./SimpleJSON

JObject [("foo",JNumber 1.0),("bar",JBool False)]

使用runghc执行：

adeMacBook-Pro:haskell_dev apple$ runghc SimpleJSON.hs

JObject [("foo",JNumber 1.0),("bar",JBool False)]