Safe Haskell	None
Language	GHC2021

Howl.Builtins.ToBuiltin

Description

Convert Haskell functions into builtin Howl rules.

Synopsis

class ToBuiltin f where
- toBuiltin :: f -> Seq Expr -> Eval (Maybe Expr)
newtype Variadic a b = MkVariadic (Seq a -> b)
def :: ToBuiltin f => Symbol -> f -> Eval ()
builtinDecl :: ToBuiltin f => Symbol -> f -> Decl

Documentation

class ToBuiltin f where #

Given a function type f, turn it into an operation on a Seq Expr, interpreted as the arguments to a symbolic function.

We provide instances for return types that can reasonably be turned into rules, where the final result type is any instance of ToExpr.

Methods

toBuiltin :: f -> Seq Expr -> Eval (Maybe Expr) #

Instances

Instances details

ToExpr a => ToBuiltin a #	A pure builtin that always matches its arguments.
Instance details Defined in Howl.Builtins.ToBuiltin Methods toBuiltin :: a -> Seq Expr -> Eval (Maybe Expr) #
ToExpr a => ToBuiltin (Eval (Maybe a)) #	A monadic builtin that may fail to match its arguments, signified by `Nothing`.
Instance details Defined in Howl.Builtins.ToBuiltin Methods toBuiltin :: Eval (Maybe a) -> Seq Expr -> Eval (Maybe Expr) #
ToExpr a => ToBuiltin (Eval a) #	A monadic builtin that always matches its arguments.
Instance details Defined in Howl.Builtins.ToBuiltin Methods toBuiltin :: Eval a -> Seq Expr -> Eval (Maybe Expr) #
ToExpr a => ToBuiltin (Maybe a) #	A pure builtin that may fail to match its arguments, signified by `Nothing`.
Instance details Defined in Howl.Builtins.ToBuiltin Methods toBuiltin :: Maybe a -> Seq Expr -> Eval (Maybe Expr) #
(FromExpr a, ToExpr b) => ToBuiltin (Variadic a (Eval (Maybe b))) #	A variadic monadic builtin that may fail to match its arguments, signified by `Nothing`.
Instance details Defined in Howl.Builtins.ToBuiltin Methods toBuiltin :: Variadic a (Eval (Maybe b)) -> Seq Expr -> Eval (Maybe Expr) #
(FromExpr a, ToExpr b) => ToBuiltin (Variadic a (Eval b)) #	A variadic monadic builtin that always matches its arguments.
Instance details Defined in Howl.Builtins.ToBuiltin Methods toBuiltin :: Variadic a (Eval b) -> Seq Expr -> Eval (Maybe Expr) #
(FromExpr a, ToExpr b) => ToBuiltin (Variadic a (Maybe b)) #	A variadic pure builtin that may fail to match its arguments, signified by `Nothing`.
Instance details Defined in Howl.Builtins.ToBuiltin Methods toBuiltin :: Variadic a (Maybe b) -> Seq Expr -> Eval (Maybe Expr) #
(FromExpr a, ToExpr b) => ToBuiltin (Variadic a b) #	A variadic pure builtin that always matches its arguments.
Instance details Defined in Howl.Builtins.ToBuiltin Methods toBuiltin :: Variadic a b -> Seq Expr -> Eval (Maybe Expr) #
(FromExpr a, ToBuiltin f) => ToBuiltin (a -> f) #	Provide instances for functions of the form `a -> b -> ... -> r`, where `r` is one of the return types above and `a`, `b`, ... are instances of `FromExpr`. Together, these instances allow us to "lift" most reasonable Haskell functions to functions that can be used inside rules. Here are some example types that have instances for `ToBuiltin`: Integer -> Double -> Text -> Bool Symbol -> Maybe Double Expr -> Integer -> Eval (Maybe Numeric)
Instance details Defined in Howl.Builtins.ToBuiltin Methods toBuiltin :: (a -> f) -> Seq Expr -> Eval (Maybe Expr) #

newtype Variadic a b #

Mark a function as variadic, i.e. as taking a Seq a of arbitrary length as its argument list.

Constructors

MkVariadic (Seq a -> b)

Instances

Instances details

(FromExpr a, ToExpr b) => ToBuiltin (Variadic a (Eval (Maybe b))) #	A variadic monadic builtin that may fail to match its arguments, signified by `Nothing`.
Instance details Defined in Howl.Builtins.ToBuiltin Methods toBuiltin :: Variadic a (Eval (Maybe b)) -> Seq Expr -> Eval (Maybe Expr) #
(FromExpr a, ToExpr b) => ToBuiltin (Variadic a (Eval b)) #	A variadic monadic builtin that always matches its arguments.
Instance details Defined in Howl.Builtins.ToBuiltin Methods toBuiltin :: Variadic a (Eval b) -> Seq Expr -> Eval (Maybe Expr) #
(FromExpr a, ToExpr b) => ToBuiltin (Variadic a (Maybe b)) #	A variadic pure builtin that may fail to match its arguments, signified by `Nothing`.
Instance details Defined in Howl.Builtins.ToBuiltin Methods toBuiltin :: Variadic a (Maybe b) -> Seq Expr -> Eval (Maybe Expr) #
(FromExpr a, ToExpr b) => ToBuiltin (Variadic a b) #	A variadic pure builtin that always matches its arguments.
Instance details Defined in Howl.Builtins.ToBuiltin Methods toBuiltin :: Variadic a b -> Seq Expr -> Eval (Maybe Expr) #

def :: ToBuiltin f => Symbol -> f -> Eval () #

Define a builtin rule by converting a Haskell function into a Howl definition using ToBuiltin.

builtinDecl :: ToBuiltin f => Symbol -> f -> Decl #

Convert a Haskell function into a declaration for a builtin downvalue.