class RDoc::MethodAttr

def block_params=(value)
  # 'yield.to_s' or 'assert yield, msg'
  return @block_params = '' if value =~ /^[\.,]/
  # remove trailing 'if/unless ...'
  return @block_params = '' if value =~ /^(if|unless)\s/
  value = $1.strip if value =~ /^(.+)\s(if|unless)\s/
  # outer parentheses
  value = $1 if value =~ /^\s*\((.*)\)\s*$/
  value = value.strip
  # proc/lambda
  return @block_params = $1 if value =~ /^(proc|lambda)(\s*\{|\sdo)/
  # surrounding +...+ or [...]
  value = $1.strip if value =~ /^\+(.*)\+$/
  value = $1.strip if value =~ /^\[(.*)\]$/
  return @block_params = '' if value.empty?
  # global variable
  return @block_params = 'str' if value =~ /^\$[&0-9]$/
  # wipe out array/hash indices
  value.gsub!(/(\w)\[[^\[]+\]/, '\1')
  # remove @ from class/instance variables
  value.gsub!(/@@?([a-z0-9_]+)/, '\1')
  # method calls => method name
  value.gsub!(/([A-Z:a-z0-9_]+)\.([a-z0-9_]+)(\s*\(\s*[a-z0-9_.,\s]*\s*\)\s*)?/) do
    case $2
    when 'to_s'      then $1
    when 'const_get' then 'const'
    when 'new' then
      $1.split('::').last.  # ClassName => class_name
        gsub(/([A-Z]+)([A-Z][a-z])/, '\1_\2').
        gsub(/([a-z\d])([A-Z])/, '\1_\2').
        downcase
    else
      $2
    end
  end
  # class prefixes
  value.gsub!(/[A-Za-z0-9_:]+::/, '')
  # simple expressions
  value = $1 if value =~ /^([a-z0-9_]+)\s*[-*+\/]/
  @block_params = value.strip
end