244 lines
6.8 KiB
Ruby
244 lines
6.8 KiB
Ruby
# frozen_string_literal: true
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require 'singleton'
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# See also `app/javascript/features/account/util/bio_metadata.js`.
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class FrontmatterHandler
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include Singleton
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# CONVENIENCE FUNCTIONS #
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def self.unirex(str)
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Regexp.new str, Regexp::MULTILINE, 'u'
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end
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def self.rexstr(exp)
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'(?:' + exp.source + ')'
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end
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# CHARACTER CLASSES #
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DOCUMENT_START = /^/
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DOCUMENT_END = /$/
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ALLOWED_CHAR = # c-printable` in the YAML 1.2 spec.
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/[\t\n\r\u{20}-\u{7e}\u{85}\u{a0}-\u{d7ff}\u{e000}-\u{fffd}\u{10000}-\u{10ffff}]/u
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WHITE_SPACE = /[ \t]/
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INDENTATION = / */
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LINE_BREAK = /\r?\n|\r|<br\s*\/?>/
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ESCAPE_CHAR = /[0abt\tnvfre "\/\\N_LP]/
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HEXADECIMAL_CHARS = /[0-9a-fA-F]/
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INDICATOR = /[-?:,\[\]{}&#*!|>'"%@`]/
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FLOW_CHAR = /[,\[\]{}]/
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# NEGATED CHARACTER CLASSES #
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NOT_WHITE_SPACE = unirex '(?!' + rexstr(WHITE_SPACE) + ').'
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NOT_LINE_BREAK = unirex '(?!' + rexstr(LINE_BREAK) + ').'
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NOT_INDICATOR = unirex '(?!' + rexstr(INDICATOR) + ').'
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NOT_FLOW_CHAR = unirex '(?!' + rexstr(FLOW_CHAR) + ').'
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NOT_ALLOWED_CHAR = unirex '(?!' + rexstr(ALLOWED_CHAR) + ').'
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# BASIC CONSTRUCTS #
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ANY_WHITE_SPACE = unirex rexstr(WHITE_SPACE) + '*'
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ANY_ALLOWED_CHARS = unirex rexstr(ALLOWED_CHAR) + '*'
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NEW_LINE = unirex(
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rexstr(ANY_WHITE_SPACE) + rexstr(LINE_BREAK)
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)
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SOME_NEW_LINES = unirex(
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'(?:' + rexstr(ANY_WHITE_SPACE) + rexstr(LINE_BREAK) + ')+'
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)
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POSSIBLE_STARTS = unirex(
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rexstr(DOCUMENT_START) + rexstr(/<p[^<>]*>/) + '?'
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)
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POSSIBLE_ENDS = unirex(
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rexstr(SOME_NEW_LINES) + '|' +
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rexstr(DOCUMENT_END) + '|' +
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rexstr(/<\/p>/)
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)
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CHARACTER_ESCAPE = unirex(
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rexstr(/\\/) +
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'(?:' +
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rexstr(ESCAPE_CHAR) + '|' +
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rexstr(/x/) + rexstr(HEXADECIMAL_CHARS) + '{2}' + '|' +
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rexstr(/u/) + rexstr(HEXADECIMAL_CHARS) + '{4}' + '|' +
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rexstr(/U/) + rexstr(HEXADECIMAL_CHARS) + '{8}' +
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')'
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)
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ESCAPED_CHAR = unirex(
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rexstr(/(?!["\\])/) + rexstr(NOT_LINE_BREAK) + '|' +
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rexstr(CHARACTER_ESCAPE)
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)
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ANY_ESCAPED_CHARS = unirex(
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rexstr(ESCAPED_CHAR) + '*'
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)
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ESCAPED_APOS = unirex(
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'(?=' + rexstr(NOT_LINE_BREAK) + ')' + rexstr(/[^']|''/)
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)
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ANY_ESCAPED_APOS = unirex(
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rexstr(ESCAPED_APOS) + '*'
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)
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FIRST_KEY_CHAR = unirex(
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'(?=' + rexstr(NOT_LINE_BREAK) + ')' +
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'(?=' + rexstr(NOT_WHITE_SPACE) + ')' +
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rexstr(NOT_INDICATOR) + '|' +
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rexstr(/[?:-]/) +
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'(?=' + rexstr(NOT_LINE_BREAK) + ')' +
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'(?=' + rexstr(NOT_WHITE_SPACE) + ')' +
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'(?=' + rexstr(NOT_FLOW_CHAR) + ')'
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)
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FIRST_VALUE_CHAR = unirex(
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'(?=' + rexstr(NOT_LINE_BREAK) + ')' +
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'(?=' + rexstr(NOT_WHITE_SPACE) + ')' +
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rexstr(NOT_INDICATOR) + '|' +
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rexstr(/[?:-]/) +
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'(?=' + rexstr(NOT_LINE_BREAK) + ')' +
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'(?=' + rexstr(NOT_WHITE_SPACE) + ')'
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# Flow indicators are allowed in values.
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)
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LATER_KEY_CHAR = unirex(
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rexstr(WHITE_SPACE) + '|' +
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'(?=' + rexstr(NOT_LINE_BREAK) + ')' +
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'(?=' + rexstr(NOT_WHITE_SPACE) + ')' +
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'(?=' + rexstr(NOT_FLOW_CHAR) + ')' +
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rexstr(/[^:#]#?/) + '|' +
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rexstr(/:/) + '(?=' + rexstr(NOT_WHITE_SPACE) + ')'
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)
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LATER_VALUE_CHAR = unirex(
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rexstr(WHITE_SPACE) + '|' +
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'(?=' + rexstr(NOT_LINE_BREAK) + ')' +
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'(?=' + rexstr(NOT_WHITE_SPACE) + ')' +
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# Flow indicators are allowed in values.
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rexstr(/[^:#]#?/) + '|' +
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rexstr(/:/) + '(?=' + rexstr(NOT_WHITE_SPACE) + ')'
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)
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# YAML CONSTRUCTS #
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YAML_START = unirex(
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rexstr(ANY_WHITE_SPACE) + rexstr(/---/)
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)
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YAML_END = unirex(
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rexstr(ANY_WHITE_SPACE) + rexstr(/(?:---|\.\.\.)/)
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)
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YAML_LOOKAHEAD = unirex(
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'(?=' +
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rexstr(YAML_START) +
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rexstr(ANY_ALLOWED_CHARS) + rexstr(NEW_LINE) +
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rexstr(YAML_END) + rexstr(POSSIBLE_ENDS) +
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')'
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)
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YAML_DOUBLE_QUOTE = unirex(
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rexstr(/"/) + rexstr(ANY_ESCAPED_CHARS) + rexstr(/"/)
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)
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YAML_SINGLE_QUOTE = unirex(
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rexstr(/'/) + rexstr(ANY_ESCAPED_APOS) + rexstr(/'/)
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)
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YAML_SIMPLE_KEY = unirex(
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rexstr(FIRST_KEY_CHAR) + rexstr(LATER_KEY_CHAR) + '*'
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)
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YAML_SIMPLE_VALUE = unirex(
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rexstr(FIRST_VALUE_CHAR) + rexstr(LATER_VALUE_CHAR) + '*'
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)
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YAML_KEY = unirex(
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rexstr(YAML_DOUBLE_QUOTE) + '|' +
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rexstr(YAML_SINGLE_QUOTE) + '|' +
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rexstr(YAML_SIMPLE_KEY)
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)
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YAML_VALUE = unirex(
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rexstr(YAML_DOUBLE_QUOTE) + '|' +
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rexstr(YAML_SINGLE_QUOTE) + '|' +
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rexstr(YAML_SIMPLE_VALUE)
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)
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YAML_SEPARATOR = unirex(
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rexstr(ANY_WHITE_SPACE) +
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':' + rexstr(WHITE_SPACE) +
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rexstr(ANY_WHITE_SPACE)
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)
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YAML_LINE = unirex(
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'(' + rexstr(YAML_KEY) + ')' +
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rexstr(YAML_SEPARATOR) +
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'(' + rexstr(YAML_VALUE) + ')'
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)
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# FRONTMATTER REGEX #
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YAML_FRONTMATTER = unirex(
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rexstr(POSSIBLE_STARTS) +
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rexstr(YAML_LOOKAHEAD) +
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rexstr(YAML_START) + rexstr(SOME_NEW_LINES) +
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'(?:' +
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'(' + rexstr(INDENTATION) + ')' +
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rexstr(YAML_LINE) + rexstr(SOME_NEW_LINES) +
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'(?:' +
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'\\1' + rexstr(YAML_LINE) + rexstr(SOME_NEW_LINES) +
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'){0,4}' +
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')?' +
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rexstr(YAML_END) + rexstr(POSSIBLE_ENDS)
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)
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# SEARCHES #
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FIND_YAML_LINES = unirex(
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rexstr(NEW_LINE) + rexstr(INDENTATION) + rexstr(YAML_LINE)
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)
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# STRING PROCESSING #
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def process_string(str)
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case str[0]
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when '"'
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str[1..-2]
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.gsub(/\\0/, "\u{00}")
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.gsub(/\\a/, "\u{07}")
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.gsub(/\\b/, "\u{08}")
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.gsub(/\\t/, "\u{09}")
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.gsub(/\\\u{09}/, "\u{09}")
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.gsub(/\\n/, "\u{0a}")
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.gsub(/\\v/, "\u{0b}")
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.gsub(/\\f/, "\u{0c}")
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.gsub(/\\r/, "\u{0d}")
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.gsub(/\\e/, "\u{1b}")
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.gsub(/\\ /, "\u{20}")
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.gsub(/\\"/, "\u{22}")
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.gsub(/\\\//, "\u{2f}")
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.gsub(/\\\\/, "\u{5c}")
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.gsub(/\\N/, "\u{85}")
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.gsub(/\\_/, "\u{a0}")
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.gsub(/\\L/, "\u{2028}")
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.gsub(/\\P/, "\u{2029}")
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.gsub(/\\x([0-9a-fA-F]{2})/mu) {|s| $1.to_i.chr Encoding::UTF_8}
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.gsub(/\\u([0-9a-fA-F]{4})/mu) {|s| $1.to_i.chr Encoding::UTF_8}
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.gsub(/\\U([0-9a-fA-F]{8})/mu) {|s| $1.to_i.chr Encoding::UTF_8}
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when "'"
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str[1..-2].gsub(/''/, "'")
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else
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str
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end
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end
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# BIO PROCESSING #
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def process_bio content
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result = {
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text: content.gsub(/"/, '"').gsub(/'/, "'"),
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metadata: []
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}
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yaml = YAML_FRONTMATTER.match(result[:text])
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return result unless yaml
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yaml = yaml[0]
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start = YAML_START =~ result[:text]
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ending = start + yaml.length - (YAML_START =~ yaml)
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result[:text][start..ending - 1] = ''
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metadata = nil
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index = 0
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while metadata = FIND_YAML_LINES.match(yaml, index) do
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index = metadata.end(0)
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result[:metadata].push [
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process_string(metadata[1]), process_string(metadata[2])
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]
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end
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return result
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end
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end
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