Futhark.Script

FutharkScript is a (tiny) subset of Futhark used to write small expressions that are evaluated by server executables. The futhark literate command is the main user.

Server

data ScriptServer

Like a Server, but keeps a bit more state to make FutharkScript more convenient.

withScriptServer :: FilePath -> [FilePath] -> (ScriptServer -> IO a) -> IO a

Start a server, execute an action, then shut down the server. Similar to withServer.

Expressions, values, and types

data Func

A function called in a Call expression can be either a Futhark function or a builtin function.

Constructors

FuncFut EntryName

FuncBuiltin Text

Instances

Show Func

Defined in Futhark.Script

Methods

showsPrec :: Int -> Func -> ShowS

show :: Func -> String

showList :: [Func] -> ShowS

Pretty Func

Defined in Futhark.Script

Methods

ppr :: Func -> Doc

pprPrec :: Int -> Func -> Doc

pprList :: [Func] -> Doc

data Exp

A FutharkScript expression. This is a simple AST that might not correspond exactly to what the user wrote (e.g. no parentheses or source locations). This is fine for small expressions, which is all this is meant for.

Constructors

Call Func [Exp]

Const PrimValue

Tuple [Exp]

Record [(Text, Exp)]

StringLit Text

ServerVar TypeName VarName

Server-side variable, *not* Futhark variable (these are handled in Call).

Instances

Show Exp

Defined in Futhark.Script

Methods

showsPrec :: Int -> Exp -> ShowS

show :: Exp -> String

showList :: [Exp] -> ShowS

Pretty Exp

Defined in Futhark.Script

Methods

ppr :: Exp -> Doc

pprPrec :: Int -> Exp -> Doc

pprList :: [Exp] -> Doc

parseExp :: Parser () -> Parser Exp

Parse a FutharkScript expression.

varsInExp :: Exp -> Set EntryName

The set of Futhark variables that are referenced by the expression - these will have to be entry points in the Futhark program.

data ScriptValueType

The type of a ScriptValue - either a value type or a function type.

Constructors

STValue TypeName

STFun [TypeName] [TypeName]

Ins, then outs.

Instances

Eq ScriptValueType

Defined in Futhark.Script

Methods

(==) :: ScriptValueType -> ScriptValueType -> Bool

(/=) :: ScriptValueType -> ScriptValueType -> Bool

Show ScriptValueType

Defined in Futhark.Script

Methods

showsPrec :: Int -> ScriptValueType -> ShowS

show :: ScriptValueType -> String

showList :: [ScriptValueType] -> ShowS

Pretty ScriptValueType

Defined in Futhark.Script

Methods

ppr :: ScriptValueType -> Doc

pprPrec :: Int -> ScriptValueType -> Doc

pprList :: [ScriptValueType] -> Doc

data ScriptValue v

A ScriptValue is either a base value or a partially applied function. We don't have real first-class functions in FutharkScript, but we sort of have closures.

Constructors

SValue TypeName v

SFun EntryName [TypeName] [TypeName] [ScriptValue v]

Ins, then outs. Yes, this is the opposite of more or less everywhere else.

Instances

Functor ScriptValue

Defined in Futhark.Script

Methods

fmap :: (a -> b) -> ScriptValue a -> ScriptValue b

(<$) :: a -> ScriptValue b -> ScriptValue a

Foldable ScriptValue

Defined in Futhark.Script

Methods

fold :: Monoid m => ScriptValue m -> m

foldMap :: Monoid m => (a -> m) -> ScriptValue a -> m

foldMap' :: Monoid m => (a -> m) -> ScriptValue a -> m

foldr :: (a -> b -> b) -> b -> ScriptValue a -> b

foldr' :: (a -> b -> b) -> b -> ScriptValue a -> b

foldl :: (b -> a -> b) -> b -> ScriptValue a -> b

foldl' :: (b -> a -> b) -> b -> ScriptValue a -> b

foldr1 :: (a -> a -> a) -> ScriptValue a -> a

foldl1 :: (a -> a -> a) -> ScriptValue a -> a

toList :: ScriptValue a -> [a]

null :: ScriptValue a -> Bool

length :: ScriptValue a -> Int

elem :: Eq a => a -> ScriptValue a -> Bool

maximum :: Ord a => ScriptValue a -> a

minimum :: Ord a => ScriptValue a -> a

sum :: Num a => ScriptValue a -> a

product :: Num a => ScriptValue a -> a

Traversable ScriptValue

Defined in Futhark.Script

Methods

traverse :: Applicative f => (a -> f b) -> ScriptValue a -> f (ScriptValue b)

sequenceA :: Applicative f => ScriptValue (f a) -> f (ScriptValue a)

mapM :: Monad m => (a -> m b) -> ScriptValue a -> m (ScriptValue b)

sequence :: Monad m => ScriptValue (m a) -> m (ScriptValue a)

scriptValueType :: ScriptValue v -> ScriptValueType

The type of a ScriptValue.

type ExpValue = Compound (ScriptValue VarName)

The value that is produced by expression evaluation. This representation keeps all values on the server.

Evaluation

type EvalBuiltin m = Text -> [CompoundValue] -> m CompoundValue

How to evaluate a builtin function.

evalExp :: forall m. (MonadError Text m, MonadIO m) => EvalBuiltin m -> ScriptServer -> Exp -> m ExpValue

Evaluate a FutharkScript expression relative to some running server.

getExpValue :: (MonadError Text m, MonadIO m) => ScriptServer -> ExpValue -> m CompoundValue

Read actual values from the server. Fails for values that have no well-defined external representation.

evalExpToGround :: (MonadError Text m, MonadIO m) => EvalBuiltin m -> ScriptServer -> Exp -> m (Either (Compound ScriptValueType) CompoundValue)

Like evalExp, but requires all values to be non-functional. If the value has a bad type, return that type instead. Other evaluation problems (e.g. type failures) raise errors.

valueToExp :: ExpValue -> Exp

Convert a value into a corresponding expression.

freeValue :: (MonadError Text m, MonadIO m) => ScriptServer -> ExpValue -> m ()

Release all the server-side variables in the value. Yes, FutharkScript has manual memory management...