[Haskell-beginners] How to compile stub?

[Zhi-Qiang Lei]

Hi,

My attempt which compiles some files with stub failed. Can you tell me how to compile them? Thanks.

PrettyJSON.hs:

renderJValue :: JValue -> Doc
renderJValue (JBool True)  = text "true"
renderJValue (JBool False) = text "false"
renderJValue JNull         = text "null"
renderJValue (JNumber num) = double num
renderJValue (JString str) = string str

PrettyStub.hs:

import SimpleJSON

data Doc = ToBeDefined
         deriving (Show)

string :: String -> Doc
string str = undefined

text :: String -> Doc
text str = undefined

double :: Double -> Doc
double num = undefined


Result:

bogon% ghc -c PrettyJSON.hs PrettyStub.hs SimpleJSON.o
Warning: the following files would be used as linker inputs, but linking is not being done: SimpleJSON.o

PrettyJSON.hs:1:16:
    Not in scope: type constructor or class `JValue'

PrettyJSON.hs:1:26: Not in scope: type constructor or class `Doc'

PrettyJSON.hs:2:14: Not in scope: data constructor `JBool'

PrettyJSON.hs:2:29: Not in scope: `text'

PrettyJSON.hs:3:14: Not in scope: data constructor `JBool'

PrettyJSON.hs:3:29: Not in scope: `text'

PrettyJSON.hs:4:13: Not in scope: data constructor `JNull'

PrettyJSON.hs:4:29: Not in scope: `text'

PrettyJSON.hs:5:14: Not in scope: data constructor `JNumber'

PrettyJSON.hs:5:29: Not in scope: `double'

PrettyJSON.hs:6:14: Not in scope: data constructor `JString'

PrettyJSON.hs:6:29: Not in scope: `string'

Best regards,
Zhi-Qiang Lei
zhiqiang.lei at gmail.com