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deriveSafeCopySimpleIndexedType :: Version a -> Name -> Name -> [Name] -> Q [Dec]

safecopy Data.SafeCopy

No documentation available.

safecopy	Data.SafeCopy

deriveSafeCopy :: Version a -> Name -> Name -> Q [Dec]

safecopy	Data.SafeCopy.Internal

Derive an instance of SafeCopy. When serializing, we put a Word8 describing the constructor (if the data type has more than one constructor). For each type used in the constructor, we call getSafePut (which immediately serializes the version of the type). Then, for each field in the constructor, we use one of the put functions obtained in the last step. For example, given the data type and the declaration below

data T0 b = T0 b Int
deriveSafeCopy 1 'base ''T0

we generate

instance (SafeCopy a, SafeCopy b) =>
SafeCopy (T0 b) where
putCopy (T0 arg1 arg2) = contain $ do put_b   <- getSafePut
put_Int <- getSafePut
put_b   arg1
put_Int arg2
return ()
getCopy = contain $ do get_b   <- getSafeGet
get_Int <- getSafeGet
return T0 <*> get_b <*> get_Int
version = 1
kind = base

And, should we create another data type as a newer version of T0, such as

data T a b = C a a | D b Int
deriveSafeCopy 2 'extension ''T

instance SafeCopy b => Migrate (T a b) where
type MigrateFrom (T a b) = T0 b
migrate (T0 b i) = D b i

we generate

instance (SafeCopy a, SafeCopy b) =>
SafeCopy (T a b) where
putCopy (C arg1 arg2) = contain $ do putWord8 0
put_a <- getSafePut
put_a arg1
put_a arg2
return ()
putCopy (D arg1 arg2) = contain $ do putWord8 1
put_b   <- getSafePut
put_Int <- getSafePut
put_b   arg1
put_Int arg2
return ()
getCopy = contain $ do tag <- getWord8
case tag of
0 -> do get_a <- getSafeGet
return C <*> get_a <*> get_a
1 -> do get_b   <- getSafeGet
get_Int <- getSafeGet
return D <*> get_b <*> get_Int
_ -> fail $ "Could not identify tag \"" ++
show tag ++ "\" for type Main.T " ++
"that has only 2 constructors.  " ++
"Maybe your data is corrupted?"
version = 2
kind = extension

Note that by using getSafePut, we saved 4 bytes in the case of the C constructor. For D and T0, we didn't save anything. The instance derived by this function always use at most the same space as those generated by deriveSafeCopySimple, but never more (as we don't call getSafePut/getSafeGet for types that aren't needed). Note that you may use deriveSafeCopySimple with one version of your data type and deriveSafeCopy in another version without any problems.

deriveSafeCopyHappstackData :: Version a -> Name -> Name -> Q [Dec]

safecopy Data.SafeCopy.Internal

Derive an instance of SafeCopy. The instance derived by this function should be compatible with the instance derived by the module Happstack.Data.SerializeTH of the happstack-data package. The instances use only safePut and safeGet (as do the instances created by deriveSafeCopySimple), but we also always write a Word8 tag, even if the data type isn't a sum type. For example, given the data type and the declaration below
```
data T0 b = T0 b Int
deriveSafeCopy 1 'base ''T0
```
we generate
```
instance (SafeCopy a, SafeCopy b) =>
SafeCopy (T0 b) where
putCopy (T0 arg1 arg2) = contain $ do putWord8 0
safePut arg1
safePut arg2
return ()
getCopy = contain $ do tag <- getWord8
case tag of
0 -> do return T0 <*> safeGet <*> safeGet
_ -> fail $ "Could not identify tag \"" ++
show tag ++ "\" for type Main.T0 " ++
"that has only 1 constructors.  " ++
"Maybe your data is corrupted?"
version = 1
kind = base
```
This instance always consumes at least the same space as deriveSafeCopy or deriveSafeCopySimple, but may use more because of the useless tag. So we recomend using it only if you really need to read a previous version in this format, and not for newer versions. Note that you may use deriveSafeCopy with one version of your data type and deriveSafeCopyHappstackData in another version without any problems.
deriveSafeCopyHappstackDataIndexedType :: Version a -> Name -> Name -> [Name] -> Q [Dec]

safecopy Data.SafeCopy.Internal

No documentation available.
deriveSafeCopyIndexedType :: Version a -> Name -> Name -> [Name] -> Q [Dec]

safecopy Data.SafeCopy.Internal

No documentation available.
deriveSafeCopySimple :: Version a -> Name -> Name -> Q [Dec]

safecopy Data.SafeCopy.Internal

Derive an instance of SafeCopy. The instance derived by this function is simpler than the one derived by deriveSafeCopy in that we always use safePut and safeGet (instead of getSafePut and getSafeGet). When serializing, we put a Word8 describing the constructor (if the data type has more than one constructor) and, for each field of the constructor, we use safePut. For example, given the data type and the declaration below
```
data T a b = C a a | D b Int
deriveSafeCopySimple 1 'base ''T
```
we generate
```
instance (SafeCopy a, SafeCopy b) =>
SafeCopy (T a b) where
putCopy (C arg1 arg2) = contain $ do putWord8 0
safePut arg1
safePut arg2
return ()
putCopy (D arg1 arg2) = contain $ do putWord8 1
safePut arg1
safePut arg2
return ()
getCopy = contain $ do tag <- getWord8
case tag of
0 -> do return C <*> safeGet <*> safeGet
1 -> do return D <*> safeGet <*> safeGet
_ -> fail $ "Could not identify tag \"" ++
show tag ++ "\" for type Main.T " ++
"that has only 2 constructors.  " ++
"Maybe your data is corrupted?"
version = 1
kind = base
```
Using this simpler instance means that you may spend more bytes when serializing data. On the other hand, it is more straightforward and may match any other format you used in the past. Note that you may use deriveSafeCopy with one version of your data type and deriveSafeCopySimple in another version without any problems.
deriveSafeCopySimpleIndexedType :: Version a -> Name -> Name -> [Name] -> Q [Dec]

safecopy Data.SafeCopy.Internal

No documentation available.
deriveTextShow :: Name -> Q [Dec]

text-show TextShow.TH

Generates a TextShow instance declaration for the given data type or data family instance. Since: 2
deriveTextShow1 :: Name -> Q [Dec]

text-show TextShow.TH

Generates a TextShow1 instance declaration for the given data type or data family instance. Since: 2
deriveTextShow1Options :: Options -> Name -> Q [Dec]

text-show TextShow.TH

Like deriveTextShow1, but takes an Options argument. Since: 3.4

text-show	TextShow.TH

text-show	TextShow.TH

text-show	TextShow.TH

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