Safe Haskell	Safe
Language	Haskell98

Language.Haskell.Lexer

Synopsis

Documentation

type PosToken = (Token, (Pos, String)) Source #

data Token Source #

Haskell token classifications:

Constructors

Varid	Variable
Conid	Constructor
Varsym	Variable operator
Consym	Constructor operator
Reservedid	Reserved keyword
Reservedop	Reserved operator
Specialid
IntLit	Integral numeric literal
FloatLit	Fractional numeric literal
CharLit	Character literal
StringLit	String literal
Qvarid	Qualified variable
Qconid	Qualified constructor
Qvarsym	Qualified variable operator
Qconsym	Qualified constructor operator
Special
Whitespace	White space
NestedCommentStart	Internal: causes a call to an external function
NestedComment	A nested comment ({- ... -})
LiterateComment	Not handled by the lexer
Commentstart	Dashes
Comment	The stuff after the dashes
ErrorToken
GotEOF
TheRest
ModuleName
ModuleAlias	recognized in a later pass
Layout	for implicit braces
Indent Int	<n>, to preceed first token on each line
Open Int	{n}, after let, where, do or of, if not followed by a "{"

Instances

Eq Token Source #
Methods (==) :: Token -> Token -> Bool # (/=) :: Token -> Token -> Bool #
Ord Token Source #
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 Source #
Methods showsPrec :: Int -> Token -> ShowS # show :: Token -> String # showList :: [Token] -> ShowS #

lexerPass0 :: String -> [PosToken] Source #

Tokenize and add position information. Preserves white space, and does not insert extra tokens due to layout.

lexerPass0' :: Pos -> String -> [PosToken] Source #

Same as lexerPass0, except that it uses the given start position.

lexerPass1 :: String -> [PosToken] Source #

The function lexerPass1 handles the part of lexical analysis that can be done independently of the parser---the tokenization and the addition of the extra layout tokens <n> and {n}, as specified in section 9.3 of the revised Haskell 98 Report.

rmSpace :: [PosToken] -> [PosToken] Source #

Remove token that are not meaningful (e.g., white space and comments).

layoutPre :: [PosToken] -> [PosToken] Source #

This is an implementation of Haskell layout, as specified in section 9.3 of the revised Haskell 98 report. This preprocessor inserts the extra <n> and {n} tokens.

data Pos Source #

The posisiotn within a file.

Constructors

Pos
Fields char, line, column :: !Int

Instances

Eq Pos Source #
Methods (==) :: Pos -> Pos -> Bool # (/=) :: Pos -> Pos -> Bool #
Ord Pos Source #
Methods compare :: Pos -> Pos -> Ordering # (<) :: Pos -> Pos -> Bool # (<=) :: Pos -> Pos -> Bool # (>) :: Pos -> Pos -> Bool # (>=) :: Pos -> Pos -> Bool # max :: Pos -> Pos -> Pos # min :: Pos -> Pos -> Pos #
Show Pos Source #
Methods showsPrec :: Int -> Pos -> ShowS # show :: Pos -> String # showList :: [Pos] -> ShowS #

simpPos :: Pos -> (Int, Int) Source #

The line and column numbers of a position.

startPos :: Pos Source #

The first column is designated column 1, not 0.

nextPos :: Pos -> String -> Pos Source #

Advance position by a string.

nextPos1 :: Pos -> Char -> Pos Source #

Advance position by a single character.