Language.ContextFree.CfgM

Portability	portable
Stability	provisional
Maintainer	jas@di.uminho.pt

Contents

Context-free grammars with actions.
Examples

Description

Regular Expressions in Haskell. Code Included in the Lecture Notes on Language Processing (with a functional flavour).

Synopsis

data Cfg m sy = Cfg {

terminals :: [sy]

nonterminals :: [sy]

root :: sy

prods :: [[(sy, m)]]

}

type ProdM m sy = (sy, m)

(|->) :: a -> [a] -> [a]

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

($->) :: Monad m => a -> [(a, m ())] -> [(a, m ())]

(<$$>) :: MonadState s m => t -> (s -> s) -> (t, m ())

(<*>) :: a -> [a] -> [a]

(<$*>) :: Monad m => a -> [(a, m ())] -> [(a, m ())]

exExpa :: MonadState Int m => Cfg (m ()) [Char]

data Exp

= AddExp Exp Exp

| MulExp Exp Exp

| Number Int

| Var String

exExpb :: MonadState [Exp] m => Cfg (m ()) [Char]

exExpc :: MonadState [Exp] m => Cfg (m ()) [Char]

Context-free grammars with actions.

data Cfg m sy

Datatype of context-free grammars with actions.

Constructors

Cfg

terminals :: [sy]
nonterminals :: [sy]
root :: sy
prods :: [[(sy, m)]]

Instances

(Show sy, ??? m sy) => Show (Cfg m sy)

type ProdM m sy = (sy, m)

Type synonym for productions with actions

(|->) :: a -> [a] -> [a]

Create a production from LHS and RHS.

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

Create a production with action from a production and an action.

($->) :: Monad m => a -> [(a, m ())] -> [(a, m ())]

Create a production with empty LHS action.

(<$$>) :: MonadState s m => t -> (s -> s) -> (t, m ())

Create a production with a state-modifying action

(<*>) :: a -> [a] -> [a]

Construct list of RHS symbols with actions. The first argument is a symbol with action.

(<$*>) :: Monad m => a -> [(a, m ())] -> [(a, m ())]

Construct list of RHS symbols with actions. The first argument is a symbol without action.

Examples

exExpa :: MonadState Int m => Cfg (m ()) [Char]

data Exp

Constructors

AddExp Exp Exp
MulExp Exp Exp
Number Int
Var String

exExpb :: MonadState [Exp] m => Cfg (m ()) [Char]

exExpc :: MonadState [Exp] m => Cfg (m ()) [Char]

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