-- Copyright 2006-2018 Mitchell mitchell.att.foicica.com. See License.txt.
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-- YAML LPeg lexer.
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-- It does not keep track of indentation perfectly.
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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 M = {_NAME = 'yaml'}
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-- Whitespace.
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local indent = #lexer.starts_line(S(' \t')) *
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(token(lexer.WHITESPACE, ' ') + token('indent_error', '\t'))^1
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local ws = token(lexer.WHITESPACE, S(' \t')^1 + lexer.newline^1)
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-- Comments.
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local comment = token(lexer.COMMENT, '#' * lexer.nonnewline^0)
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-- Strings.
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local string = token(lexer.STRING, lexer.delimited_range("'") +
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lexer.delimited_range('"'))
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-- Numbers.
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local integer = lexer.dec_num + lexer.hex_num + '0' * S('oO') * R('07')^1
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local special_num = '.' * word_match({'inf', 'nan'}, nil, true)
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local number = token(lexer.NUMBER, special_num + lexer.float + integer)
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-- Timestamps.
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local ts = token('timestamp',
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lexer.digit * lexer.digit * lexer.digit * lexer.digit * -- year
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'-' * lexer.digit * lexer.digit^-1 * -- month
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'-' * lexer.digit * lexer.digit^-1 * -- day
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((S(' \t')^1 + S('tT'))^-1 * -- separator
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lexer.digit * lexer.digit^-1 * -- hour
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':' * lexer.digit * lexer.digit * -- minute
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':' * lexer.digit * lexer.digit * -- second
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('.' * lexer.digit^0)^-1 * -- fraction
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('Z' + -- timezone
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S(' \t')^0 * S('-+') * lexer.digit * lexer.digit^-1 *
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(':' * lexer.digit * lexer.digit)^-1)^-1)^-1)
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-- Constants.
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local constant = token(lexer.CONSTANT,
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word_match({'null', 'true', 'false'}, nil, true))
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-- Types.
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local type = token(lexer.TYPE, '!!' * word_match({
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-- Collection types.
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'map', 'omap', 'pairs', 'set', 'seq',
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-- Scalar types.
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'binary', 'bool', 'float', 'int', 'merge', 'null', 'str', 'timestamp',
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'value', 'yaml'
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}, nil, true) + '!' * lexer.delimited_range('<>'))
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-- Document boundaries.
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local doc_bounds = token('document', lexer.starts_line(P('---') + '...'))
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-- Directives
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local directive = token('directive', lexer.starts_line('%') *
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lexer.nonnewline^1)
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local word = (lexer.alpha + '-' * -lexer.space) * (lexer.alnum + '-')^0
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-- Keys and literals.
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local colon = S(' \t')^0 * ':' * (lexer.space + -1)
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local key = token(lexer.KEYWORD,
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#word * (lexer.nonnewline - colon)^1 * #colon *
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P(function(input, index)
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local line = input:sub(1, index - 1):match('[^\r\n]+$')
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return not line:find('[%w-]+:') and index
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end))
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local value = #word * (lexer.nonnewline - lexer.space^0 * S(',]}'))^1
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local block = S('|>') * S('+-')^-1 * (lexer.newline + -1) *
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function(input, index)
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local rest = input:sub(index)
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local level = #rest:match('^( *)')
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for pos, indent, line in rest:gmatch('() *()([^\r\n]+)') do
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if indent - pos < level and line ~= ' ' or
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level == 0 and pos > 1 then
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return index + pos - 1
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end
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end
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return #input + 1
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end
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local literal = token('literal', value + block)
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-- Indicators.
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local anchor = token(lexer.LABEL, '&' * word)
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local alias = token(lexer.VARIABLE, '*' * word)
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local tag = token('tag', '!' * word * P('!')^-1)
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local reserved = token(lexer.ERROR, S('@`') * word)
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local indicator_chars = token(lexer.OPERATOR, S('-?:,[]{}!'))
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M._rules = {
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{'indent', indent},
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{'whitespace', ws},
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{'comment', comment},
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{'doc_bounds', doc_bounds},
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{'key', key},
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{'literal', literal},
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{'timestamp', ts},
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{'number', number},
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{'constant', constant},
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{'type', type},
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{'indicator', tag + indicator_chars + alias + anchor + reserved},
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{'directive', directive},
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}
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M._tokenstyles = {
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indent_error = 'back:%(color.red)',
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document = lexer.STYLE_CONSTANT,
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literal = lexer.STYLE_DEFAULT,
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timestamp = lexer.STYLE_NUMBER,
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tag = lexer.STYLE_CLASS,
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directive = lexer.STYLE_PREPROCESSOR,
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}
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M._FOLDBYINDENTATION = true
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return M
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