Class: MTProto::Markdown::Renderer

Inherits:
Object
  • Object
show all
Defined in:
lib/mtproto/markdown.rb

Overview

entities -> MarkdownV2 markup. Escapes literal markup characters and wraps each entity's UTF-16 range with its markers. Entities are opened outer-first and closed inner-first so proper nesting round-trips. Works in UTF-16 unit space.

Constant Summary collapse

SPECIAL = 
'_*[]()~`>#+-=|{}.!\\'
WRAP = 
{ bold: '*', italic: '_', underline: '__', strike: '~', spoiler: '||' }.freeze

Instance Method Summary collapse

Constructor Details

#initialize(text, entities) ⇒ Renderer

Returns a new instance of Renderer.



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# File 'lib/mtproto/markdown.rb', line 338

def initialize(text, entities)
  @units = (text || '').encode('UTF-16LE').unpack('v*')
  @entities = (entities || []).map { |e| e.is_a?(Hash) ? Entity.new(**e) : e }
end

Instance Method Details

#render ⇒ Object 



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# File 'lib/mtproto/markdown.rb', line 343

def render
  opens = Hash.new { |h, k| h[k] = [] }
  closes = Hash.new { |h, k| h[k] = [] }
  @entities.each_with_index do |e, i|
    opens[e.offset] << [e, i]
    closes[e.offset + e.length] << [e, i]
  end
  verbatim = ranges_of(%i[code pre]) # content here is literal — never escaped
  quotes = ranges_of(%i[blockquote]) # rendered as a '>' line prefix

  out = +''
  pos = 0
  line_start = true
  loop do
    # Close inner-first, the exact mirror of the open order (outer-first), so
    # entities that end together don't emit crossed markers. Ties broken by the
    # reverse of the open tiebreak.
    closes[pos].sort_by { |(e, i)| [e.length, -i] }.each { |(e, _)| out << close_marker(e) }
    out << '>' if line_start && in_range?(quotes, pos)
    opens[pos].sort_by { |(e, i)| [-e.length, i] }.each { |(e, _)| out << open_marker(e) }
    break if pos >= @units.length

    u = @units[pos]
    if high_surrogate?(u) && pos + 1 < @units.length
      out << pair_to_s(u, @units[pos + 1]) # an astral char never needs escaping
      pos += 2
      line_start = false
    else
      ch = unit_to_s(u)
      out << render_char(ch, in_range?(verbatim, pos))
      line_start = ch == "\n"
      pos += 1
    end
  end
  out
end