-- Copyright 2006-2018 Mitchell mitchell.att.foicica.com. See License.txt.
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-- Postscript LPeg lexer.
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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('ps')
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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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pop exch dup copy roll clear count mark cleartomark counttomark exec if ifelse
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for repeat loop exit stop stopped countexecstack execstack quit start
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true false NULL
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]]))
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-- Functions.
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lex:add_rule('function', token(lexer.FUNCTION, word_match[[
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add div idiv mod mul sub abs ned ceiling floor round truncate sqrt atan cos
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sin exp ln log rand srand rrand
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]]))
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-- Identifiers.
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local word = (lexer.alpha + '-') * (lexer.alnum + '-')^0
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lex:add_rule('identifier', token(lexer.IDENTIFIER, word))
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-- Strings.
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local arrow_string = lexer.delimited_range('<>')
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local nested_string = lexer.delimited_range('()', false, false, true)
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lex:add_rule('string', token(lexer.STRING, arrow_string + nested_string))
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-- Comments.
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lex:add_rule('comment', token(lexer.COMMENT, '%' * lexer.nonnewline^0))
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-- Numbers.
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lex:add_rule('number', token(lexer.NUMBER, lexer.float + lexer.integer))
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-- Labels.
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lex:add_rule('label', token(lexer.LABEL, '/' * word))
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-- Operators.
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lex:add_rule('operator', token(lexer.OPERATOR, S('[]{}')))
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return lex
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