Copyright	(c) Eric Mertens 2023
License	ISC
Maintainer	emertens@gmail.com
Safe Haskell	Safe-Inferred
Language	Haskell2010

Toml.Lexer.Utils

Contents

Types
Input processing
Actions
String literals

Description

This module provides a custom engine for the Alex generated lexer. This lexer drive provides nested states, unicode support, and file location tracking.

The various states of this module are needed to deal with the varying lexing rules while lexing values, keys, and string-literals.

Synopsis

type Action = Located String -> State [Context] [Located Token]
data Context
- = ListContext Position
- | TableContext Position
- | ValueContext
- | MlStrContext Position [String]
- | StrContext Position [String]
locatedUncons :: Located String -> Maybe (Int, Located String)
value :: (String -> Token) -> Action
value_ :: Token -> Action
token :: (String -> Token) -> Action
token_ :: Token -> Action
squareO :: Action
squareC :: Action
curlyO :: Action
curlyC :: Action
equals :: Action
timeValue :: ParseTime a => String -> [String] -> (a -> Token) -> Action
eofToken :: [Context] -> Located String -> Located Token
strFrag :: Action
startMlStr :: Action
startStr :: Action
endStr :: Action
unicodeEscape :: Action

Types

type Action = Located String -> State [Context] [Located Token] Source #

Type of actions associated with lexer patterns

data Context Source #

Representation of the current lexer state.

Constructors

ListContext Position	processing an inline list, lex values
TableContext Position	processing an inline table, don't lex values
ValueContext	processing after an equals, lex one value
MlStrContext Position [String]	position of opening delimiter and list of fragments
StrContext Position [String]	position of opening delimiter and list of fragments

Instances

Instances details

Show Context Source #
Instance details Defined in Toml.Lexer.Utils Methods showsPrec :: Int -> Context -> ShowS # show :: Context -> String # showList :: [Context] -> ShowS #

Input processing

locatedUncons :: Located String -> Maybe (Int, Located String) Source #

Pop the first character off a located string if it's not empty. The resulting Int will either be the ASCII value of the character or 1 for non-ASCII Unicode values. To avoid a clash, x1 is remapped to 0.