Module: MarkdownComposer::Take

Defined in:
lib/markdown_composer/take.rb

Class Method Summary collapse

Class Method Details

.alternate_indexes(count, group_size) ⇒ Object 



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# File 'lib/markdown_composer/take.rb', line 125

def alternate_indexes(count, group_size)
  (0...count).select { |index| ((index / group_size) % 2).zero? }
end

.apply(items, take, diagnostics: nil, path: nil, seed: 0) ⇒ Object 



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# File 'lib/markdown_composer/take.rb', line 39

def apply(items, take, diagnostics: nil, path: nil, seed: 0)
  take = parse(take) if take.is_a?(String) || take.is_a?(Symbol)
  take ||= { "all" => true }
  errors = validate(take)
  errors.each { |message| diagnostics&.error("take.invalid", message, path: path) }
  return [] if errors.any?
  return items.dup if take.empty? || take["all"]

  selected_indexes = []
  count = items.length

  selected_indexes.concat((0...[take["first"].to_i, count].min).to_a) if take["first"]
  selected_indexes.concat(((count - take["last"].to_i)...count).to_a) if take["last"]
  selected_indexes.concat(Array(take["position"]).map { |position| resolve_position(position, count) }.compact) if take["position"]
  Array(take["ranges"]).each do |range|
    from = resolve_position(range["from"], count)
    to = resolve_position(range["to"], count)
    selected_indexes.concat((from..to).to_a) if from && to && from <= to
  end

  if take["skip"]
    selected_indexes = (take["skip"].to_i...count).to_a
  end
  if take["skip_last"]
    selected_indexes = (0...[count - take["skip_last"].to_i, 0].max).to_a
  end
  selected_indexes = (0...count).select { |index| (index + 1) % take["every"].to_i == 0 } if take["every"]
  selected_indexes = (0...count).select { |index| (index + 1).odd? } if take["odd"]
  selected_indexes = (0...count).select { |index| (index + 1).even? } if take["even"]
  selected_indexes = (0...count).to_a - Array(take["except"]).map { |position| resolve_position(position, count) }.compact if take["except"]
  selected_indexes = percent_indexes(count, take["top_percent"].to_i, :top) if take["top_percent"]
  selected_indexes = percent_indexes(count, take["bottom_percent"].to_i, :bottom) if take["bottom_percent"]
  selected_indexes = middle_indexes(count, take["middle"].to_i) if take["middle"]
  selected_indexes = middle_indexes(count, (count * take["middle_percent"].to_i / 100.0).ceil) if take["middle_percent"]
  selected_indexes = alternate_indexes(count, take["alternate"].to_i) if take["alternate"]
  selected_indexes = (0...count).to_a.sample(take["random"].to_i, random: Random.new(seed)).sort if take["random"]

  selected_indexes.uniq.sort.map { |index| items[index] }.compact
end

.integer(value) ⇒ Object 



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# File 'lib/markdown_composer/take.rb', line 102

def integer(value)
  value.to_s == "last" ? -1 : value.to_i
end

.middle_indexes(count, selected_count) ⇒ Object 



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# File 'lib/markdown_composer/take.rb', line 119

def middle_indexes(count, selected_count)
  selected_count = [ selected_count, count ].min
  start = [(count - selected_count) / 2, 0].max
  (start...(start + selected_count)).to_a
end

.parse(value) ⇒ Object 



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# File 'lib/markdown_composer/take.rb', line 7

def parse(value)
  text = value.to_s.strip
  text = text[1..-2] if text.start_with?("[") && text.end_with?("]")
  return { "all" => true } if text.empty? || text == "all"

  clauses = text.split(";").map(&:strip)
  clauses.each_with_object({}) do |clause, hash|
    case clause
    when /\Aodd\z/
      hash["odd"] = true
    when /\Aeven\z/
      hash["even"] = true
    when /\A(\d+|-?\d+)\.\.(last|-?\d+|\d+)\z/
      (hash["ranges"] ||= []) << { "from" => integer(Regexp.last_match(1)), "to" => integer(Regexp.last_match(2)) }
    when /\A([^:]+):(.+)\z/
      key = Regexp.last_match(1).strip
      raw = Regexp.last_match(2).strip
      case key
      when "position", "except"
        hash[key] = raw.split(",").map { |part| integer(part.strip) }
      when "range"
        from, to = raw.split("..", 2)
        (hash["ranges"] ||= []) << { "from" => integer(from), "to" => integer(to) }
      else
        hash[key] = integer(raw)
      end
    else
      hash[clause] = true
    end
  end
end

.percent_indexes(count, percent, direction) ⇒ Object 



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# File 'lib/markdown_composer/take.rb', line 114

def percent_indexes(count, percent, direction)
  selected_count = (count * percent / 100.0).ceil
  direction == :top ? (0...selected_count).to_a : ((count - selected_count)...count).to_a
end

.resolve_position(position, count) ⇒ Object 



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# File 'lib/markdown_composer/take.rb', line 106

def resolve_position(position, count)
  value = position.to_i
  return nil if value.zero?

  index = value.positive? ? value - 1 : count + value
  index if index >= 0 && index < count
end

.validate(take) ⇒ Object 



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# File 'lib/markdown_composer/take.rb', line 79

def validate(take)
  errors = []
  take.each do |key, value|
    unless Registries.default.take.key?(key.to_sym)
      errors << "Unknown take operator #{key.inspect}"
      next
    end

    case key
    when "first", "last", "skip", "skip_last", "every", "top_percent", "bottom_percent", "middle", "middle_percent", "alternate", "random"
      errors << "#{key} must be positive" if value.to_i <= 0
    when "position", "except"
      Array(value).each { |position| errors << "#{key} cannot include 0" if position.to_i.zero? }
    when "ranges"
      Array(value).each do |range|
        errors << "range is missing from/to" unless range.key?("from") && range.key?("to")
        errors << "range cannot include 0" if range["from"].to_i.zero? || range["to"].to_i.zero?
      end
    end
  end
  errors
end