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-- Copyright 2006-2020 Mitchell mitchell.att.foicica.com. See License.txt.
-- Io LPeg lexer.
local lexer = require('lexer')
local token, word_match = lexer.token, lexer.word_match
local P, S = lpeg.P, lpeg.S
local lex = lexer.new('io_lang')
-- Whitespace.
lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space^1))
-- Keywords.
lex:add_rule('keyword', token(lexer.KEYWORD, word_match[[
block method while foreach if else do super self clone proto setSlot hasSlot
type write print forward
]]))
-- Types.
lex:add_rule('type', token(lexer.TYPE, word_match[[
Block Buffer CFunction Date Duration File Future LinkedList List Map Message
Nil Nop Number Object String WeakLink
]]))
-- Identifiers.
lex:add_rule('identifier', token(lexer.IDENTIFIER, lexer.word))
-- Strings.
local sq_str = lexer.range("'")
local dq_str = lexer.range('"')
local tq_str = lexer.range('"""')
lex:add_rule('string', token(lexer.STRING, tq_str + sq_str + dq_str))
-- Comments.
local line_comment = lexer.to_eol(P('#') + '//')
local block_comment = lexer.range('/*', '*/')
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,
S('`~@$%^&*-+/=\\<>?.,:;()[]{}')))
-- Fold points.
lex:add_fold_point(lexer.OPERATOR, '(', ')')
lex:add_fold_point(lexer.COMMENT, '/*', '*/')
lex:add_fold_point(lexer.COMMENT, lexer.fold_consecutive_lines('//'))
return lex
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