haskell-generate-0.2.2: haskell-generate

Safe HaskellNone




newtype Generate a Source

This monad keeps track of a counter for generating unique names and the set of modules that are needed for the expression.




unGenerate :: StateT Integer (Writer (Set ModuleName)) a


Monad Generate 
Functor Generate 
Applicative Generate 
Num t => Num (ExpG t) 
GenExp (ExpG a) 
GenExp x => GenExp (ExpG a -> x) 

type ExpG t = Generate (Expression t)Source

This is a type alias for a Generate action that returns an expression of type t.

runGenerate :: Generate a -> (a, Set ModuleName)Source

Extract the set of modules and the value from a Generate action.

newName :: String -> Generate NameSource

Generate a new unique variable name with the given prefix. Note that this new variable name is only unique relative to other variable names generated by this function.

returnE :: Exp -> ExpG tSource

Use a haskell-src-exts Exp as the result of a Generate action.

useValue :: String -> Name -> ExpG aSource

Import a function from a module. This function is polymorphic in the type of the resulting expression, you should probably only use this function to define type-restricted specializations.


 addInt :: ExpG (Int -> Int -> Int) -- Here we restricted the type to something sensible
 addInt = useValue "Prelude" $ Symbol "+"

useCon :: String -> Name -> Generate QNameSource

Import a value constructor from a module. Returns the qualified name of the constructor.

useVar :: Name -> ExpG tSource

Use the value of a variable with the given name.

caseE :: ExpG x -> [(Pat, ExpG t)] -> ExpG tSource

Generate a case expression.

applyE :: ExpG (a -> b) -> ExpG a -> ExpG bSource

Apply a function in a haskell expression to a value.

applyE2 :: ExpG (a -> b -> c) -> ExpG a -> ExpG b -> ExpG cSource

ApplyE for 2 arguments

applyE3 :: ExpG (a -> b -> c -> d) -> ExpG a -> ExpG b -> ExpG c -> ExpG dSource

Apply a function to 3 arguments

applyE4 :: ExpG (a -> b -> c -> d -> e) -> ExpG a -> ExpG b -> ExpG c -> ExpG d -> ExpG eSource

Apply a function to 4 arguments

applyE5 :: ExpG (a -> b -> c -> d -> e -> f) -> ExpG a -> ExpG b -> ExpG c -> ExpG d -> ExpG e -> ExpG fSource

Apply a function to 5 arguments

applyE6 :: ExpG (a -> b -> c -> d -> e -> f -> g) -> ExpG a -> ExpG b -> ExpG c -> ExpG d -> ExpG e -> ExpG f -> ExpG gSource

Apply a function to 6 arguments

(<>$) :: ExpG (a -> b) -> ExpG a -> ExpG bSource

Operator for applyE.

class GenExp t whereSource

Generate a expression from a haskell value. This can for example be used to create lambdas:

>>> putStrLn $ generateExp $ expr (\x f -> f <>$ x)
\ pvar_0 -> \ pvar_1 -> pvar_1 pvar_0

Or string literals:

>>> putStrLn $ generateExp $ expr "I'm a string!"
['I', '\'', 'm', ' ', 'a', ' ', 's', 't', 'r', 'i', 'n', 'g', '!']

Associated Types

type GenExpType t :: *Source


expr :: t -> ExpG (GenExpType t)Source

This function generates the haskell expression from the given haskell value.


GenExp Char 
GenExp Integer 
GenExp Rational 
GenExp a => GenExp [a] 
GenExp (Expression t) 
GenExp (FunRef t) 
GenExp (ExpG a) 
GenExp x => GenExp (ExpG a -> x) 

newtype ModuleM a Source

A module keeps track of the needed imports, but also has a list of declarations in it.


ModuleM (Writer (Set ModuleName, [Decl]) a) 


Monad ModuleM 
Functor ModuleM 
Applicative ModuleM 

type ModuleG = ModuleM (Maybe [ExportSpec])Source

This is the resulting type of a function generating a module. It is a ModuleM action returning the export list.

data FunRef t Source

A reference to a function. With a reference to a function, you can apply it (by lifting it into ExprT using expr) to some value or export it using exportFun.


FunRef Name 


data Name

This type is used to represent variables, and also constructors.


Ident String

varid or conid.

Symbol String

varsym or consym


Eq Name 
Data Name 
Ord Name 
Show Name 
Typeable Name 
Generic Name 
Pretty Name 

exportFun :: FunRef t -> ExportSpecSource

Generate a ExportSpec for a given function item.

addDecl :: Name -> ExpG t -> ModuleM (FunRef t)Source

Add a declaration to the module. Return a reference to it that can be used to either apply the function to some values or export it.

runModuleM :: ModuleG -> String -> ModuleSource

Extract the Module from a module generator.

generateModule :: ModuleG -> String -> StringSource

Generate the source code for a module.

generateExp :: ExpG t -> StringSource

Pretty print the expression generated by a given action.