Data.Emacs.Module.Args

Documentation

data Nat

Type-level Peano numbers.

Indented to be used with DataKinds extension enabled.

Constructors

Z

S Nat

type family EmacsArgs (req :: Nat) (opt :: Nat) (rest :: Bool) (a :: Type) = (r :: Type) | r -> req opt rest a where ...

Specification of the arguments that exposed functions can receive from Emacs.

This type family allows to declaratively specify how many required and optional arguments a function can take and whether it accepts rest arguments. It's a direct translation of argument lists in Emacs lisp, e.g.

(defun foo (x y z &optional w t &rest quux)
  (+ (* x y z) (* (or w 1) (or t 2)) (length quux)))

The function above has 3 required arguments, 2 optional and also has rest arguments. The type family below has two Nats and one Bool to provide that info.

Equations

EmacsArgs ('S n) opt rest a = R a (EmacsArgs n opt rest a)

EmacsArgs 'Z ('S k) rest a = O a (EmacsArgs 'Z k rest a)

EmacsArgs 'Z 'Z 'True a = Rest a

EmacsArgs 'Z 'Z 'False a = Stop a

class EmacsInvocation req opt rest where

Methods

supplyEmacsArgs :: MonadBase IO m => Int -> Ptr RawValue -> (RawValue -> m a) -> (EmacsArgs req opt rest a -> m b) -> m b

Instances

EmacsInvocation 'Z 'Z 'False

Defined in Data.Emacs.Module.Args

Methods

supplyEmacsArgs :: MonadBase IO m => Int -> Ptr RawValue -> (RawValue -> m a) -> (EmacsArgs 'Z 'Z 'False a -> m b) -> m b

EmacsInvocation 'Z 'Z 'True

Defined in Data.Emacs.Module.Args

Methods

supplyEmacsArgs :: MonadBase IO m => Int -> Ptr RawValue -> (RawValue -> m a) -> (EmacsArgs 'Z 'Z 'True a -> m b) -> m b

EmacsInvocation 'Z n rest => EmacsInvocation 'Z ('S n) rest

Defined in Data.Emacs.Module.Args

Methods

supplyEmacsArgs :: MonadBase IO m => Int -> Ptr RawValue -> (RawValue -> m a) -> (EmacsArgs 'Z ('S n) rest a -> m b) -> m b

EmacsInvocation n opt rest => EmacsInvocation ('S n) opt rest

Defined in Data.Emacs.Module.Args

Methods

supplyEmacsArgs :: MonadBase IO m => Int -> Ptr RawValue -> (RawValue -> m a) -> (EmacsArgs ('S n) opt rest a -> m b) -> m b

class GetArities (req :: Nat) (opt :: Nat) (rest :: Bool) where

Helper to retrieve number of arguments a function takes for Emacs.

Methods

arities :: Proxy req -> Proxy opt -> Proxy rest -> (CPtrdiff, CPtrdiff)

Instances

NatValue req => GetArities req opt 'True

Defined in Data.Emacs.Module.Args

Methods

arities :: Proxy req -> Proxy opt -> Proxy 'True -> (CPtrdiff, CPtrdiff)

(NatValue req, NatValue opt) => GetArities req opt 'False

Defined in Data.Emacs.Module.Args

Methods

arities :: Proxy req -> Proxy opt -> Proxy 'False -> (CPtrdiff, CPtrdiff)

Argument inference

data R a b

Required argument of an exported function.

Constructors

R !a !b

data O a b

Optional argument of an exported function.

Constructors

O !(Maybe a) !b

newtype Rest a

All other arguments of an exported function as a list.

Constructors

Rest [a]

data Stop a

End of argument list of an exported funciton.

Constructors

Stop