elm.lua (1368B)
- -- Copyright 2020-2024 Mitchell. See LICENSE.
- -- Elm LPeg lexer
- -- Adapted from Haskell LPeg lexer by Karl Schultheisz.
- local lexer = require('lexer')
- local token, word_match = lexer.token, lexer.word_match
- local P, S = lpeg.P, lpeg.S
- local lex = lexer.new('elm', {fold_by_indentation = true})
- -- Whitespace.
- lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space^1))
- -- Keywords.
- lex:add_rule('keyword', token(lexer.KEYWORD, word_match(
- 'if then else case of let in module import as exposing type alias port')))
- -- Types & type constructors.
- local word = (lexer.alnum + S("._'#"))^0
- local op = lexer.punct - S('()[]{}')
- lex:add_rule('type', token(lexer.TYPE, lexer.upper * word + ':' * (op^1 - ':')))
- -- Identifiers.
- lex:add_rule('identifier', token(lexer.IDENTIFIER, (lexer.alpha + '_') * word))
- -- Strings.
- lex:add_rule('string', token(lexer.STRING, lexer.range('"')))
- -- Chars.
- lex:add_rule('character', token(lexer.STRING, lexer.range("'", true)))
- -- Comments.
- local line_comment = lexer.to_eol('--', true)
- local block_comment = lexer.range('{-', '-}', false, false, true)
- lex:add_rule('comment', token(lexer.COMMENT, line_comment + block_comment))
- -- Numbers.
- lex:add_rule('number', token(lexer.NUMBER, lexer.number))
- -- Operators.
- lex:add_rule('operator', token(lexer.OPERATOR, op))
- lexer.property['scintillua.comment'] = '--'
- return lex