GLL.Types.Grammar

Documentation

type Nt = Text

Identifier for nonterminals.

data Prod t

A production binds a nonterminal identifier (left-hand side) to a list of symbols (the right-hand side of the production).

Constructors

Prod Nt (Symbols t)

Instances

Eq t => Eq (Prod t)

Methods

(==) :: Prod t -> Prod t -> Bool

(/=) :: Prod t -> Prod t -> Bool

Ord t => Ord (Prod t)

Methods

compare :: Prod t -> Prod t -> Ordering

(<) :: Prod t -> Prod t -> Bool

(<=) :: Prod t -> Prod t -> Bool

(>) :: Prod t -> Prod t -> Bool

(>=) :: Prod t -> Prod t -> Bool

max :: Prod t -> Prod t -> Prod t

min :: Prod t -> Prod t -> Prod t

Show t => Show (Prod t)

Methods

showsPrec :: Int -> Prod t -> ShowS

show :: Prod t -> String

showList :: [Prod t] -> ShowS

type Prods t = [Prod t]

A list of Prods.

type Grammar t = (Nt, Prods t)

A grammar is a start symbol and a list of productions.

data Slot t

A grammar slot acts as a label to identify progress of matching a production. As such, a slot is a Prod with its right-hand side split in two: a part before and a part after 'the dot'. The dot indicates which part of the right-hand side has been processed thus far.

Constructors

Slot Nt [Symbol t] [Symbol t]

Instances

Eq t => Eq (Slot t)

Methods

(==) :: Slot t -> Slot t -> Bool

(/=) :: Slot t -> Slot t -> Bool

Ord t => Ord (Slot t)

Methods

compare :: Slot t -> Slot t -> Ordering

(<) :: Slot t -> Slot t -> Bool

(<=) :: Slot t -> Slot t -> Bool

(>) :: Slot t -> Slot t -> Bool

(>=) :: Slot t -> Slot t -> Bool

max :: Slot t -> Slot t -> Slot t

min :: Slot t -> Slot t -> Slot t

Show t => Show (Slot t)

Methods

showsPrec :: Int -> Slot t -> ShowS

show :: Slot t -> String

showList :: [Slot t] -> ShowS

data Symbol t

A Symbol is either a nonterminal or a terminal, where a terminal contains some arbitrary token.

Constructors

Nt Nt

Term t

Instances

Eq t => Eq (Symbol t)

Methods

(==) :: Symbol t -> Symbol t -> Bool

(/=) :: Symbol t -> Symbol t -> Bool

Ord t => Ord (Symbol t)

Methods

compare :: Symbol t -> Symbol t -> Ordering

(<) :: Symbol t -> Symbol t -> Bool

(<=) :: Symbol t -> Symbol t -> Bool

(>) :: Symbol t -> Symbol t -> Bool

(>=) :: Symbol t -> Symbol t -> Bool

max :: Symbol t -> Symbol t -> Symbol t

min :: Symbol t -> Symbol t -> Symbol t

Show t => Show (Symbol t)

Methods

showsPrec :: Int -> Symbol t -> ShowS

show :: Symbol t -> String

showList :: [Symbol t] -> ShowS

type Symbols t = [Symbol t]

A list of Symbols

data Token

A datatype for representing tokens with some builtins and an aribitrary Token constructor. This datatype stores (optional) lexemes.

Constructors

Char Char

Keyword String

EOS

Epsilon

IntLit (Maybe Int)

FloatLit (Maybe Double)

BoolLit (Maybe Bool)

StringLit (Maybe String)

CharLit (Maybe Char)

IDLit (Maybe String)

AltIDLit (Maybe String)

alternative identifiers, for example functions vs. constructors (as in Haskell).

Token String (Maybe String)

Instances

Eq Token

Methods

(==) :: Token -> Token -> Bool

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

Ord Token

Methods

compare :: Token -> Token -> Ordering

(<) :: Token -> Token -> Bool

(<=) :: Token -> Token -> Bool

(>) :: Token -> Token -> Bool

(>=) :: Token -> Token -> Bool

max :: Token -> Token -> Token

min :: Token -> Token -> Token

Show Token

Methods

showsPrec :: Int -> Token -> ShowS

show :: Token -> String

showList :: [Token] -> ShowS

SubsumesToken Token

Methods

upcast :: Token -> Token

downcast :: Token -> Maybe Token

Parseable Token

Methods

eos :: Token

eps :: Token

matches :: Token -> Token -> Bool

unlex :: Token -> String

type Tokens = [Token]

A list of Tokens

class (Ord a, Eq a, Show a) => Parseable a where

Class that captures elements of an input string (tokens).

• eos is the end-of-string symbol
• eps is the empty-string symbol

Both eos and eps must be distinct from eachother and from all tokens in the input string. The show instance is required to throw error messages.

Minimal complete definition

eos, eps, matches

Methods

eos :: a

eps :: a

matches :: a -> a -> Bool

This function is used for matching grammar tokens and input tokens. Override this method if, for example, your input tokens store lexemes while the grammar tokens do not

unlex :: a -> String

This function pretty-prints the Parseable type by displaying its lexeme. Default implementation is show, which should be replaced for prettier error messages.

Instances

Parseable Token

Methods

eos :: Token

eps :: Token

matches :: Token -> Token -> Bool

unlex :: Token -> String

class SubsumesToken a where

Class whose members are super-types of Token.

Minimal complete definition

upcast, downcast

Methods

upcast :: Token -> a

downcast :: a -> Maybe Token

Instances

SubsumesToken Token

Methods

upcast :: Token -> Token

downcast :: Token -> Maybe Token

unlexTokens :: [Token] -> String

Pretty-prints a list of Tokens as a concatenation of their lexemes.

unlexToken :: Token -> String

isNt :: Symbol t -> Bool

isTerm :: Symbol t -> Bool