Safe Haskell	Safe-Inferred
Language	Haskell2010

Little.Earley.Examples

Contents

Grammars
Symbols

Description

Some examples of grammars.

Synopsis

arithG :: Grammar ArithN CharT Char
aArithG :: Grammar ArithN CharT Char
lambdaG :: Grammar LambdaN CharT Char
mlG :: Grammar MlN String String
jsonG :: Grammar JsonN String String
data ArithN
- = SUM
- | PRODUCT
- | FACTOR
- | NUMBER
data LambdaN
- = LAMBDA
- | VAR
data MlN
- = TERM
- | ATOMS
- | ATOM
- | VAR'
data JsonN
- = JSON
- | OBJECT
- | ARRAY
data CharT
- = Digit
- | Alpha
- | OneOf [Char]
matchCharT :: CharT -> Char -> Bool

Grammars

arithG :: Grammar ArithN CharT Char Source #

Grammar of arithmetic expressions.

SUM     ::= PRODUCT | SUM [+-] PRODUCT
PRODUCT ::= FACTOR | PRODUCT [*/] FACTOR
FACTOR  ::= NUMBER | [(] NUMBER [)]
NUMBER  ::= [0-9] | [0-9] NUMBER

Example

pparse arithG SUM "1+2*3"

aArithG :: Grammar ArithN CharT Char Source #

Ambiguous grammar of arithmetic expressions.

SUM     ::= PRODUCT | SUM [+-] SUM
PRODUCT ::= FACTOR | PRODUCT [*/] PRODUCT
FACTOR  ::= NUMBER | [(] NUMBER [)]
NUMBER  ::= [0-9] | [0-9] NUMBER

Example

pparse aArithG SUM "1+2-3"

lambdaG :: Grammar LambdaN CharT Char Source #

Grammar of lambda expressions.

LAMBDA ::= VAR | [\] VAR [.] LAMBDA | [(] LAMBDA [)] LAMBDA
VAR    ::= [a-z]

Example

pparse lambdaG LAMBDA "\\x.x"
pparse lambdaG LAMBDA "(\\x.(x)x)\\x.(x)x"

mlG :: Grammar MlN String String Source #

ML-like syntax.

TERM ::= ATOMS
     | "fun" VAR "->" TERM
     | "let" VAR "=" TERM "in" TERM
     | "if" TERM "then" TERM
     | "if" TERM "then" TERM "else" TERM
ATOMS ::= ATOM | ATOMS ATOM
ATOM ::= VAR
     | "(" TERM ")"
VAR ::= "a" | "b" | "c" | ...

Example

Featuring the if-then-else ambiguity.

pparse mlG TERM (words "if a then if b then c else d")

jsonG :: Grammar JsonN String String Source #

JSON grammar.

JSON   ::= "null" | "true" | "false" | (number) | (string) | "{" OBJECT "}" | "[" ARRAY "]"
OBJECT ::= (string) ":" JSON | (string) ":" JSON "," OBJECT
ARRAY ::= JSON | JSON "," ARRAY

Example

pparse jsonG JSON (words "{ \"key\" : \"answer\" , \"contents\" : 42 }")

Symbols

data ArithN Source #

Non-terminals for arithmetic expressions.

Constructors

SUM
PRODUCT
FACTOR
NUMBER

Instances

Instances details

Bounded ArithN Source #
Instance details Defined in Little.Earley.Examples Methods minBound :: ArithN # maxBound :: ArithN #
Enum ArithN Source #
Instance details Defined in Little.Earley.Examples Methods succ :: ArithN -> ArithN # pred :: ArithN -> ArithN # toEnum :: Int -> ArithN # fromEnum :: ArithN -> Int # enumFrom :: ArithN -> [ArithN] # enumFromThen :: ArithN -> ArithN -> [ArithN] # enumFromTo :: ArithN -> ArithN -> [ArithN] # enumFromThenTo :: ArithN -> ArithN -> ArithN -> [ArithN] #
Eq ArithN Source #
Instance details Defined in Little.Earley.Examples Methods (==) :: ArithN -> ArithN -> Bool # (/=) :: ArithN -> ArithN -> Bool #
Ord ArithN Source #
Instance details Defined in Little.Earley.Examples Methods compare :: ArithN -> ArithN -> Ordering # (<) :: ArithN -> ArithN -> Bool # (<=) :: ArithN -> ArithN -> Bool # (>) :: ArithN -> ArithN -> Bool # (>=) :: ArithN -> ArithN -> Bool # max :: ArithN -> ArithN -> ArithN # min :: ArithN -> ArithN -> ArithN #
Show ArithN Source #
Instance details Defined in Little.Earley.Examples Methods showsPrec :: Int -> ArithN -> ShowS # show :: ArithN -> String # showList :: [ArithN] -> ShowS #

data LambdaN Source #

Non-terminals for lambda expressions.

Constructors

LAMBDA
VAR

Instances

Instances details

Bounded LambdaN Source #
Instance details Defined in Little.Earley.Examples Methods minBound :: LambdaN # maxBound :: LambdaN #
Enum LambdaN Source #
Instance details Defined in Little.Earley.Examples Methods succ :: LambdaN -> LambdaN # pred :: LambdaN -> LambdaN # toEnum :: Int -> LambdaN # fromEnum :: LambdaN -> Int # enumFrom :: LambdaN -> [LambdaN] # enumFromThen :: LambdaN -> LambdaN -> [LambdaN] # enumFromTo :: LambdaN -> LambdaN -> [LambdaN] # enumFromThenTo :: LambdaN -> LambdaN -> LambdaN -> [LambdaN] #
Eq LambdaN Source #
Instance details Defined in Little.Earley.Examples Methods (==) :: LambdaN -> LambdaN -> Bool # (/=) :: LambdaN -> LambdaN -> Bool #
Ord LambdaN Source #
Instance details Defined in Little.Earley.Examples Methods compare :: LambdaN -> LambdaN -> Ordering # (<) :: LambdaN -> LambdaN -> Bool # (<=) :: LambdaN -> LambdaN -> Bool # (>) :: LambdaN -> LambdaN -> Bool # (>=) :: LambdaN -> LambdaN -> Bool # max :: LambdaN -> LambdaN -> LambdaN # min :: LambdaN -> LambdaN -> LambdaN #
Show LambdaN Source #
Instance details Defined in Little.Earley.Examples Methods showsPrec :: Int -> LambdaN -> ShowS # show :: LambdaN -> String # showList :: [LambdaN] -> ShowS #

data MlN Source #

Non-terminals for an ML-like language.

Constructors

TERM
ATOMS
ATOM
VAR'

Instances

Instances details

Bounded MlN Source #
Instance details Defined in Little.Earley.Examples Methods minBound :: MlN # maxBound :: MlN #
Enum MlN Source #
Instance details Defined in Little.Earley.Examples Methods succ :: MlN -> MlN # pred :: MlN -> MlN # toEnum :: Int -> MlN # fromEnum :: MlN -> Int # enumFrom :: MlN -> [MlN] # enumFromThen :: MlN -> MlN -> [MlN] # enumFromTo :: MlN -> MlN -> [MlN] # enumFromThenTo :: MlN -> MlN -> MlN -> [MlN] #
Eq MlN Source #
Instance details Defined in Little.Earley.Examples Methods (==) :: MlN -> MlN -> Bool # (/=) :: MlN -> MlN -> Bool #
Ord MlN Source #
Instance details Defined in Little.Earley.Examples Methods compare :: MlN -> MlN -> Ordering # (<) :: MlN -> MlN -> Bool # (<=) :: MlN -> MlN -> Bool # (>) :: MlN -> MlN -> Bool # (>=) :: MlN -> MlN -> Bool # max :: MlN -> MlN -> MlN # min :: MlN -> MlN -> MlN #
Show MlN Source #
Instance details Defined in Little.Earley.Examples Methods showsPrec :: Int -> MlN -> ShowS # show :: MlN -> String # showList :: [MlN] -> ShowS #

data JsonN Source #

Non-terminals for JSON.

Constructors

JSON
OBJECT
ARRAY

Instances

Instances details

Bounded JsonN Source #
Instance details Defined in Little.Earley.Examples Methods minBound :: JsonN # maxBound :: JsonN #
Enum JsonN Source #
Instance details Defined in Little.Earley.Examples Methods succ :: JsonN -> JsonN # pred :: JsonN -> JsonN # toEnum :: Int -> JsonN # fromEnum :: JsonN -> Int # enumFrom :: JsonN -> [JsonN] # enumFromThen :: JsonN -> JsonN -> [JsonN] # enumFromTo :: JsonN -> JsonN -> [JsonN] # enumFromThenTo :: JsonN -> JsonN -> JsonN -> [JsonN] #
Eq JsonN Source #
Instance details Defined in Little.Earley.Examples Methods (==) :: JsonN -> JsonN -> Bool # (/=) :: JsonN -> JsonN -> Bool #
Ord JsonN Source #
Instance details Defined in Little.Earley.Examples Methods compare :: JsonN -> JsonN -> Ordering # (<) :: JsonN -> JsonN -> Bool # (<=) :: JsonN -> JsonN -> Bool # (>) :: JsonN -> JsonN -> Bool # (>=) :: JsonN -> JsonN -> Bool # max :: JsonN -> JsonN -> JsonN # min :: JsonN -> JsonN -> JsonN #
Show JsonN Source #
Instance details Defined in Little.Earley.Examples Methods showsPrec :: Int -> JsonN -> ShowS # show :: JsonN -> String # showList :: [JsonN] -> ShowS #

data CharT Source #

Basic character classes.

Constructors

Digit
Alpha
OneOf [Char]

Instances

Instances details

Eq CharT Source #
Instance details Defined in Little.Earley.Examples Methods (==) :: CharT -> CharT -> Bool # (/=) :: CharT -> CharT -> Bool #
Ord CharT Source #
Instance details Defined in Little.Earley.Examples Methods compare :: CharT -> CharT -> Ordering # (<) :: CharT -> CharT -> Bool # (<=) :: CharT -> CharT -> Bool # (>) :: CharT -> CharT -> Bool # (>=) :: CharT -> CharT -> Bool # max :: CharT -> CharT -> CharT # min :: CharT -> CharT -> CharT #
Show CharT Source #
Instance details Defined in Little.Earley.Examples Methods showsPrec :: Int -> CharT -> ShowS # show :: CharT -> String # showList :: [CharT] -> ShowS #

matchCharT :: CharT -> Char -> Bool Source #

Membership function for character classes.