| Copyright | (c) Sergey Vinokurov 2018 |
|---|---|
| License | BSD3-style (see LICENSE) |
| Maintainer | serg.foo@gmail.com |
| Safe Haskell | None |
| Language | Haskell2010 |
Emacs.Module
Contents
Description
This module is the entry point for writing Emacs extensions in Haskell.
This package, though provides a lot of wrapping around Emacs's bare C interface, still presumes some familiarity with said interface. Thus, when developnig Emacs modules it's recommended to keep a reference of the C interface around. One such reference is https://phst.github.io/emacs-modules.html.
Minimalistic example
Consider Emacs function
(defun foo (f x y z &optional w t &rest quux) (+ (funcall f (* x y z)) (* (or w 1) (or t 2)) (length quux)))
With help of this package, it may be defined as
{--}
{--}
import Data.Maybe
import Data.Emacs.Module.SymbolName.TH
import Emacs.Module
foo
:: (MonadEmacs m, Monad (m s))
=> EmacsFunction ('S ('S ('S ('S 'Z)))) ('S ('S 'Z)) 'True s m
foo (R f (R x (R y (R z (O w (O t (Rest quux))))))) = do
x' <- extractInt x
y' <- extractInt y
z' <- extractInt z
w' <- traverse extractInt w
t' <- traverse extractInt t
tmp <- makeInt (x' * y' * z')
tmp' <- extractInt =<< funcall [esym|funcall|] [f, tmp]
produceRef =<< makeInt (tmp' + fromMaybe 1 w' * fromMaybe 2 t' + length quux)
Creating Emacs dynamic module
In order to make shared object or dll callable from Emacs, a cabal project with foreign-library section has to be created. Please refer to https://github.com/sergv/emacs-module/tree/master/test for such a project.
Please note that this project will need a small C file for initialising Haskell runtime. In the project mentioned before it's present as https://github.com/sergv/emacs-module/blob/master/test/cbits/emacs_wrapper.c
Synopsis
- data EmacsM s a
- runEmacsM :: Env -> (forall s. EmacsM s a) -> IO a
- class MonadEmacs (m :: k -> Type -> Type) where
- type EmacsRef m :: k -> Type
- type EmacsReturn m :: k -> Type
- type EmacsFunction req opt rest (s :: k) (m :: k -> Type -> Type) = (Throws EmacsThrow, Throws EmacsError, Throws EmacsInternalError, Throws UserError) => EmacsArgs req opt rest (EmacsRef m s) -> m s (EmacsReturn m s)
- type EmacsFunctionExtra req opt rest extra (s :: k) (m :: k -> Type -> Type) = (Throws EmacsThrow, Throws EmacsError, Throws EmacsInternalError, Throws UserError) => EmacsArgs req opt rest (EmacsRef m s) -> Ptr extra -> m s (EmacsReturn m s)
- data Nat
- data R a b = R !a !b
- data O a b = O !(Maybe a) !b
- newtype Rest a = Rest [a]
- data Stop a = Stop
- data EmacsError = EmacsError {}
- data EmacsInternalError = EmacsInternalError {}
- reportAllErrorsToEmacs :: Env -> IO a -> ((Throws EmacsInternalError, Throws EmacsError, Throws UserError, Throws EmacsThrow) => IO a) -> IO a
- type UserPtrFinaliserType a = Ptr a -> IO ()
- type UserPtrFinaliser a = FunPtr (UserPtrFinaliserType a)
- module Emacs.Module.Functions
- module Data.Emacs.Module.Value
- data Env
- class Monad m => MonadThrow (m :: * -> *)
- class X e => Throws e
EmacsM
Concrete monad for interacting with Emacs. It provides:
- Ability to call Emacs C functions and automatically rethrows any errors (non-local exits) from elisp as Haskell exceptions.
- Tracks ownership of any produced Emacs values and communicates that to Emacs, so that GC on Emacs side will not make any values in Haskell invalid (funnily enough, this can happen!).
Parameter s serves to make ownership-tracking capabilities possible.
It's use is the same as in ST monad. That is, it creates
local threads so that no produced Emacs values can leave past runEmacsM.
Instances
runEmacsM :: Env -> (forall s. EmacsM s a) -> IO a Source #
Execute emacs interaction session using an environment supplied by Emacs.
Basic bindings
class MonadEmacs (m :: k -> Type -> Type) where Source #
A mtl-style typeclass for interacting with Emacs. Typeclass functions are mostly direct translations of emacs interface provided by 'emacs-module.h'.
For more functions please refer to Emacs.Module.Functions module.
Minimal complete definition
produceRef, nonLocalExitCheck, nonLocalExitGet, nonLocalExitSignal, nonLocalExitThrow, nonLocalExitClear, freeValue, makeFunctionExtra, funcall, funcallPrimitive, funcallPrimitive_, intern, typeOf, isNotNil, eq, extractWideInteger, makeWideInteger, extractDouble, makeDouble, extractString, makeString, extractUserPtr, makeUserPtr, assignUserPtr, extractUserPtrFinaliser, assignUserPtrFinaliser, vecGet, vecSet, vecSize
Associated Types
type EmacsRef m :: k -> Type Source #
Emacs value that is managed by the m monad. Will be cleaned up
after m finishes its execution.
type EmacsReturn m :: k -> Type Source #
Type of values that Haskell functions may returns to Emacs.
Methods
produceRef :: EmacsRef m s -> m s (EmacsReturn m s) Source #
Return an EmacsRef back to Emacs.
nonLocalExitCheck :: WithCallStack => m s (FuncallExit ()) Source #
Check whether a non-local exit is pending.
nonLocalExitGet :: WithCallStack => m s (FuncallExit (EmacsRef m s, EmacsRef m s)) Source #
Check whether a non-local exit is pending and get detailed data in case it is.
Arguments
| :: WithCallStack | |
| => EmacsRef m s | Error symbol |
| -> [EmacsRef m s] | Error data, will be converted to a list as Emacs API expects. |
| -> m s () |
Equivalent to Emacs's signal function.
NB if a non-local exit is alredy pending, this function will not
overwrite it. In order to do that, use nonLocalExitClear.
Arguments
| :: WithCallStack | |
| => EmacsRef m s | Tag |
| -> EmacsRef m s | Data |
| -> m s () |
Equivalent to Emacs's throw function.
NB if a non-local exit is alredy pending, this function will not
overwrite it. In order to do that, use nonLocalExitClear.
nonLocalExitClear :: WithCallStack => m s () Source #
Clean any pending local exits.
freeValue :: WithCallStack => EmacsRef m s -> m s () Source #
Make value eligible for collection during next GC within Emacs.
Arguments
| :: (WithCallStack, EmacsInvocation req opt rest, GetArities req opt rest) | |
| => (forall s'. EmacsFunctionExtra req opt rest extra s' m) | Haskell function to export |
| -> ByteString | Documentation |
| -> Ptr extra | Extra data to be passed to the Haskell function |
| -> m s (EmacsRef m s) |
Make Haskell function available as an anonymoucs Emacs
function. In order to be able to use it later from Emacs it should
be fed into bindFunction.
NB Each call to this function produces a small memory leak that will not be freed up. Hence, try not to create unbounded number of functions. This happens because GHC has to generate some wrapping code to convert between ccall and Haskell calling convention each time a function is exported. It is possible to free this code after function will not be used, but it's currently not supported.
Arguments
| :: WithCallStack | |
| => SymbolName | Function name |
| -> [EmacsRef m s] | Arguments |
| -> m s (EmacsRef m s) |
Invoke an Emacs function that may call back into Haskell.
Arguments
| :: WithCallStack | |
| => SymbolName | Function name |
| -> [EmacsRef m s] | Arguments |
| -> m s (EmacsRef m s) |
Invoke an Emacs function. The function should be simple and must not call back into Haskell.
Arguments
| :: WithCallStack | |
| => SymbolName | Function name |
| -> [EmacsRef m s] | Arguments |
| -> m s () |
Invoke an Emacs function and ignore its result. The function should be simple and must not call back into Haskell.
intern :: WithCallStack => SymbolName -> m s (EmacsRef m s) Source #
Convert a string to an Emacs symbol.
typeOf :: WithCallStack => EmacsRef m s -> m s (EmacsRef m s) Source #
Get type of an Emacs value as an Emacs symbol.
isNotNil :: WithCallStack => EmacsRef m s -> m s Bool Source #
Check whether Emacs value is not nil.
eq :: WithCallStack => EmacsRef m s -> EmacsRef m s -> m s Bool Source #
Primitive equality. Tests whether two symbols, integers or characters are the equal, but not much more. For more complete equality comparison do
funcallPrimitive [esym|equal|] [x, y]
extractWideInteger :: WithCallStack => EmacsRef m s -> m s Int64 Source #
Try to unpack a wide integer from a value.
makeWideInteger :: WithCallStack => Int64 -> m s (EmacsRef m s) Source #
Pack a wide integer for Emacs.
extractDouble :: WithCallStack => EmacsRef m s -> m s Double Source #
Try to unpack a floating-point number from a value.
makeDouble :: WithCallStack => Double -> m s (EmacsRef m s) Source #
Convert a floating-point number into Emacs value.
extractString :: WithCallStack => EmacsRef m s -> m s ByteString Source #
Extract string contents from an Emacs value.
makeString :: WithCallStack => ByteString -> m s (EmacsRef m s) Source #
Convert a utf8-encoded ByteString into an Emacs value.
extractUserPtr :: WithCallStack => EmacsRef m s -> m s (Ptr a) Source #
Extract a user pointer from an Emacs value.
Arguments
| :: WithCallStack | |
| => UserPtrFinaliser a | Finalisation action that will be executed when user pointer gets garbage-collected by Emacs. |
| -> Ptr a | |
| -> m s (EmacsRef m s) |
Pack a user pointer into an Emacs value.
assignUserPtr :: WithCallStack => EmacsRef m s -> Ptr a -> m s () Source #
Set user pointer to a new value
extractUserPtrFinaliser :: WithCallStack => EmacsRef m s -> m s (UserPtrFinaliser a) Source #
Extract a finaliser from an user_ptr.
assignUserPtrFinaliser :: WithCallStack => EmacsRef m s -> UserPtrFinaliser a -> m s () Source #
Assign new finaliser into an user_ptr.
vecGet :: WithCallStack => EmacsRef m s -> Int -> m s (EmacsRef m s) Source #
Extract an element from an Emacs vector.
Arguments
| :: WithCallStack | |
| => EmacsRef m s | Vector |
| -> Int | Index |
| -> EmacsRef m s | New value |
| -> m s () |
Assign an element into an Emacs vector.
vecSize :: WithCallStack => EmacsRef m s -> m s Int Source #
Get size of an Emacs vector.
Instances
Define functions callable by Emacs
type EmacsFunction req opt rest (s :: k) (m :: k -> Type -> Type) = (Throws EmacsThrow, Throws EmacsError, Throws EmacsInternalError, Throws UserError) => EmacsArgs req opt rest (EmacsRef m s) -> m s (EmacsReturn m s) Source #
Basic Haskell function that can be called by Emacs.
type EmacsFunctionExtra req opt rest extra (s :: k) (m :: k -> Type -> Type) = (Throws EmacsThrow, Throws EmacsError, Throws EmacsInternalError, Throws UserError) => EmacsArgs req opt rest (EmacsRef m s) -> Ptr extra -> m s (EmacsReturn m s) Source #
A Haskell functions that is callable by Emacs.
This type differs from EmacsFunction in that it has an extra
parameter which will result in an additional pointer being passed
to this function when it's called by Emacs. Contents of the pointer is
specified when function is exported to Emacs.
Type-level Peano numbers.
Indented to be used with DataKinds extension enabled.
Error types
data EmacsError Source #
A high-level error thrown when an Emacs function fails.
Constructors
| EmacsError | |
Fields
| |
Instances
| Show EmacsError Source # | |
Defined in Emacs.Module.Errors Methods showsPrec :: Int -> EmacsError -> ShowS # show :: EmacsError -> String # showList :: [EmacsError] -> ShowS # | |
| Exception EmacsError Source # | |
Defined in Emacs.Module.Errors Methods toException :: EmacsError -> SomeException # fromException :: SomeException -> Maybe EmacsError # displayException :: EmacsError -> String # | |
| Pretty EmacsError Source # | |
Defined in Emacs.Module.Errors | |
data EmacsInternalError Source #
A low-level error thrown when assumptions of this package are violated and it's not safe to proceed further.
Constructors
| EmacsInternalError | |
Fields | |
Instances
| Show EmacsInternalError Source # | |
Defined in Emacs.Module.Errors Methods showsPrec :: Int -> EmacsInternalError -> ShowS # show :: EmacsInternalError -> String # showList :: [EmacsInternalError] -> ShowS # | |
| Exception EmacsInternalError Source # | |
Defined in Emacs.Module.Errors Methods toException :: EmacsInternalError -> SomeException # fromException :: SomeException -> Maybe EmacsInternalError # | |
| Pretty EmacsInternalError Source # | |
Defined in Emacs.Module.Errors | |
reportAllErrorsToEmacs Source #
Arguments
| :: Env | |
| -> IO a | Result to return on error. |
| -> ((Throws EmacsInternalError, Throws EmacsError, Throws UserError, Throws EmacsThrow) => IO a) | |
| -> IO a |
Catch all errors this package might throw in an IO action and make Emacs aware of them.
This is a convenience function intended to be used around exported
initialise entry point into an Emacs module.
Other types
type UserPtrFinaliserType a = Ptr a -> IO () Source #
type UserPtrFinaliser a = FunPtr (UserPtrFinaliserType a) Source #
Reexports
module Emacs.Module.Functions
module Data.Emacs.Module.Value
Third-party reexports
class Monad m => MonadThrow (m :: * -> *) #
A class for monads in which exceptions may be thrown.
Instances should obey the following law:
throwM e >> x = throwM e
In other words, throwing an exception short-circuits the rest of the monadic computation.
Minimal complete definition
Instances
A Throws ee. Introduce a constraint with throw, and discharge it with
catch.
You may ignore the X superclass; it exists only to prevent additional
Throws instances from being created.
Instances
| Throws (Catch a) | |
Defined in Control.Exception.Safe.Checked | |