class Kramdown::Parser::Kramdown

def fetch_pattern(type, indentation)

to compute pattern when indentation is outside the 1..4 range.
precomputed patterns for indentations 1..4 and fallback expression 
def fetch_pattern(type, indentation)
  if type == :ul
    case indentation
    when 1 then %r/^( {0}[+*-])(#{PATTERN_TAIL})/o
    when 2 then %r/^( {0,1}[+*-])(#{PATTERN_TAIL})/o
    when 3 then %r/^( {0,2}[+*-])(#{PATTERN_TAIL})/o
    else %r/^( {0,3}[+*-])(#{PATTERN_TAIL})/o
    end
  elsif type == :ol
    case indentation
    when 1 then %r/^( {0}\d+\.)(#{PATTERN_TAIL})/o
    when 2 then %r/^( {0,1}\d+\.)(#{PATTERN_TAIL})/o
    when 3 then %r/^( {0,2}\d+\.)(#{PATTERN_TAIL})/o
    else %r/^( {0,3}\d+\.)(#{PATTERN_TAIL})/o
    end
  elsif type == :dl
    case indentation
    when 1 then %r/^( {0}:)(#{PATTERN_TAIL})/o
    when 2 then %r/^( {0,1}:)(#{PATTERN_TAIL})/o
    when 3 then %r/^( {0,2}:)(#{PATTERN_TAIL})/o
    else %r/^( {0,3}:)(#{PATTERN_TAIL})/o
    end
  end
end