-- Copyright 2006-2018 Mitchell mitchell.att.foicica.com. See License.txt.
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-- LPeg lexer for the Icon programming language.
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-- http://www.cs.arizona.edu/icon
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-- Contributed by Carl Sturtivant.
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local lexer = require('lexer')
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local token, word_match = lexer.token, lexer.word_match
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local P, R, S = lpeg.P, lpeg.R, lpeg.S
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local lex = lexer.new('icon')
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-- Whitespace.
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lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space^1))
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-- Keywords.
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lex:add_rule('keyword', token(lexer.KEYWORD, word_match[[
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break by case create default do else end every fail global if initial
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invocable link local next not of procedure record repeat return static suspend
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then to until while
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]]))
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-- Icon Keywords: unique to Icon.
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lex:add_rule('special_keyword', token('special_keyword', P('&') * word_match[[
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allocated ascii clock collections cset current date dateline digits dump e
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error errornumber errortext errorvalue errout fail features file host input
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lcase letters level line main null output phi pi pos progname random regions
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source storage subject time trace ucase version
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]]))
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lex:add_style('special_keyword', lexer.STYLE_TYPE)
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-- Identifiers.
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lex:add_rule('identifier', token(lexer.IDENTIFIER, lexer.word))
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-- Strings.
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lex:add_rule('string', token(lexer.STRING, lexer.delimited_range("'") +
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lexer.delimited_range('"')))
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-- Comments.
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lex:add_rule('comment', token(lexer.COMMENT, '#' * lexer.nonnewline_esc^0))
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-- Numbers.
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local radix_literal = P('-')^-1 * lexer.dec_num * S('rR') * lexer.alnum^1
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lex:add_rule('number', token(lexer.NUMBER, radix_literal + lexer.float +
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lexer.integer))
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-- Preprocessor.
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local preproc_word = word_match[[
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define else endif error ifdef ifndef include line undef
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]]
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lex:add_rule('preproc', token(lexer.PREPROCESSOR, P('$') * preproc_word))
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-- Operators.
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lex:add_rule('operator', token(lexer.OPERATOR, S('+-/*%<>~!=^&|?~@:;,.()[]{}')))
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-- Fold points.
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lex:add_fold_point(lexer.PREPROCESSOR, 'ifdef', 'endif')
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lex:add_fold_point(lexer.PREPROCESSOR, 'ifndef', 'endif')
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lex:add_fold_point(lexer.KEYWORD, 'procedure', 'end')
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lex:add_fold_point(lexer.COMMENT, '#', lexer.fold_line_comments('#'))
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return lex
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