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-- Copyright 2006-2019 Mitchell mitchell.att.foicica.com. See License.txt.
-- Postscript LPeg lexer.
local lexer = require('lexer')
local token, word_match = lexer.token, lexer.word_match
local P, R, S = lpeg.P, lpeg.R, lpeg.S
local lex = lexer.new('ps')
-- Whitespace.
lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space^1))
-- Keywords.
lex:add_rule('keyword', token(lexer.KEYWORD, word_match[[
pop exch dup copy roll clear count mark cleartomark counttomark exec if ifelse
for repeat loop exit stop stopped countexecstack execstack quit start
true false NULL
]]))
-- Functions.
lex:add_rule('function', token(lexer.FUNCTION, word_match[[
add div idiv mod mul sub abs ned ceiling floor round truncate sqrt atan cos
sin exp ln log rand srand rrand
]]))
-- Identifiers.
local word = (lexer.alpha + '-') * (lexer.alnum + '-')^0
lex:add_rule('identifier', token(lexer.IDENTIFIER, word))
-- Strings.
local arrow_string = lexer.delimited_range('<>')
local nested_string = lexer.delimited_range('()', false, false, true)
lex:add_rule('string', token(lexer.STRING, arrow_string + nested_string))
-- Comments.
lex:add_rule('comment', token(lexer.COMMENT, '%' * lexer.nonnewline^0))
-- Numbers.
lex:add_rule('number', token(lexer.NUMBER, lexer.float + lexer.integer))
-- Labels.
lex:add_rule('label', token(lexer.LABEL, '/' * word))
-- Operators.
lex:add_rule('operator', token(lexer.OPERATOR, S('[]{}')))
return lex
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