code: func newStruct(name string, def ast.Node) *Struct {
  	return &Struct{
  		symbol: symbol{
  			name: name,
  			def:  def,
  		},
  	}
  }
docs: // newStruct returns a new struct with empty list of symbols inside.
  //
  // The caller then can populate it via AddSymbol and finalize with Freeze when
  // done.