Write builders

a builder of the required type should created to which buffered statements will be applied.

No file, test, or entry point is named. Start by reading the issue's comment thread and locating the parser components that handle buffered statements and builder types; confirm the required type and expected construction flow before implementation. Done means the agreed builder exists and buffered statements can be applied to it, with tests covering that behavior.

索引モデルが issue の本文から書いたものです。