1
2-- | This module provides default values for many types.
3--   To use the default value simply write 'def'.
4module System.Console.CmdArgs.Default where
5
6import Data.Int
7import Data.Word
8
9-- | Class for default values.
10class Default a where
11    -- | Provide a default value, such as @()@, @False@, @0@, @[]@, @Nothing@.
12    def :: a
13
14instance Default () where def = ()
15instance Default Bool where def = False
16instance Default Int where def = 0
17instance Default Integer where def = 0
18instance Default Float where def = 0
19instance Default Double where def = 0
20instance Default [a] where def = []
21instance Default (Maybe a) where def = Nothing
22
23instance Default Int8 where def = 0
24instance Default Int16 where def = 0
25instance Default Int32 where def = 0
26instance Default Int64 where def = 0
27instance Default Word where def = 0
28instance Default Word8 where def = 0
29instance Default Word16 where def = 0
30instance Default Word32 where def = 0
31instance Default Word64 where def = 0
32
33-- EXPANDY: $(2\10 instance ($(1,$ Default a$)) => Default ($(1,$ a$)) where def = ($(1,$ def)))
34instance (Default a1,Default a2) => Default (a1,a2) where def = (def,def)
35instance (Default a1,Default a2,Default a3) => Default (a1,a2,a3) where def = (def,def,def)
36instance (Default a1,Default a2,Default a3,Default a4) => Default (a1,a2,a3,a4) where def = (def,def,def,def)
37instance (Default a1,Default a2,Default a3,Default a4,Default a5) => Default (a1,a2,a3,a4,a5) where def = (def,def,def,def,def)
38instance (Default a1,Default a2,Default a3,Default a4,Default a5,Default a6) => Default (a1,a2,a3,a4,a5,a6) where def = (def,def,def,def,def,def)
39instance (Default a1,Default a2,Default a3,Default a4,Default a5,Default a6,Default a7) => Default (a1,a2,a3,a4,a5,a6,a7) where def = (def,def,def,def,def,def,def)
40instance (Default a1,Default a2,Default a3,Default a4,Default a5,Default a6,Default a7,Default a8) => Default (a1,a2,a3,a4,a5,a6,a7,a8) where def = (def,def,def,def,def,def,def,def)
41instance (Default a1,Default a2,Default a3,Default a4,Default a5,Default a6,Default a7,Default a8,Default a9) => Default (a1,a2,a3,a4,a5,a6,a7,a8,a9) where def = (def,def,def,def,def,def,def,def,def)
42instance (Default a1,Default a2,Default a3,Default a4,Default a5,Default a6,Default a7,Default a8,Default a9,Default a10) => Default (a1,a2,a3,a4,a5,a6,a7,a8,a9,a10) where def = (def,def,def,def,def,def,def,def,def,def)
43