-- Copyright 2006-2018 Mitchell mitchell.att.foicica.com. See License.txt.
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-- XML 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, V = lpeg.P, lpeg.R, lpeg.S, lpeg.V
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local lex = lexer.new('xml')
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-- Whitespace.
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local ws = token(lexer.WHITESPACE, lexer.space^1)
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lex:add_rule('whitespace', ws)
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-- Comments and CDATA.
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lex:add_rule('comment', token(lexer.COMMENT, '<!--' * (lexer.any - '-->')^0 *
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P('-->')^-1))
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lex:add_rule('cdata', token('cdata', '<![CDATA[' * (lexer.any - ']]>')^0 *
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P(']]>')^-1))
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lex:add_style('cdata', lexer.STYLE_COMMENT)
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local alpha = R('az', 'AZ', '\127\255')
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local word_char = lexer.alnum + S('_-:.??')
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local identifier = (alpha + S('_-:.??')) * word_char^0
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-- Doctypes and other markup tags.
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lex:add_rule('doctype', token('doctype', P('<!DOCTYPE')) * ws *
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token('doctype', identifier) * (ws * identifier)^-1 *
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(1 - P('>'))^0 * token('doctype', '>'))
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lex:add_style('doctype', lexer.STYLE_COMMENT)
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-- Processing instructions.
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lex:add_rule('proc_insn', token('proc_insn', P('<?') * (1 - P('?>'))^0 *
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P('?>')^-1))
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lex:add_style('proc_insn', lexer.STYLE_COMMENT)
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-- Elements.
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local namespace = token(lexer.OPERATOR, ':') * token('namespace', identifier)
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lex:add_rule('element', token('element', '<' * P('/')^-1 * identifier) *
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namespace^-1)
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lex:add_style('element', lexer.STYLE_KEYWORD)
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lex:add_style('namespace', lexer.STYLE_CLASS)
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-- Closing tags.
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lex:add_rule('close_tag', token('element', P('/')^-1 * '>'))
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-- Attributes.
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lex:add_rule('attribute', token('attribute', identifier) * namespace^-1 *
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#(lexer.space^0 * '='))
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lex:add_style('attribute', lexer.STYLE_TYPE)
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-- TODO: performance is terrible on large files.
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local in_tag = P(function(input, index)
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local before = input:sub(1, index - 1)
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local s, e = before:find('<[^>]-$'), before:find('>[^<]-$')
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if s and e then return s > e and index or nil end
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if s then return index end
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return input:find('^[^<]->', index) and index or nil
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end)
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-- Equals.
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--lex:add_rule('equal', token(lexer.OPERATOR, '=')) -- * in_tag
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-- Strings.
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lex:add_rule('string', #S('\'"') * lexer.last_char_includes('=') *
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token(lexer.STRING,
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lexer.delimited_range("'", false, true) +
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lexer.delimited_range('"', false, true)))
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-- Numbers.
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lex:add_rule('number', #lexer.digit * lexer.last_char_includes('=') *
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token(lexer.NUMBER, lexer.digit^1 * P('%')^-1))--*in_tag)
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-- Entities.
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lex:add_rule('entity', token('entity', '&' * word_match[[
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lt gt amp apos quot
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]] * ';'))
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lex:add_style('entity', lexer.STYLE_OPERATOR)
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-- Fold Points.
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local function disambiguate_lt(text, pos, line, s)
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return not line:find('^</', s) and 1 or -1
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end
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lex:add_fold_point('element', '<', disambiguate_lt)
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lex:add_fold_point('element', '/>', -1)
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lex:add_fold_point(lexer.COMMENT, '<!--', '-->')
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lex:add_fold_point('cdata', '<![CDATA[', ']]>')
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return lex
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