It would be nice if Ormolu could be told to only change certain lines, and leave the rest unchanged. This can help reduce the noise in individual code changes, when automated tooling applies the formatter only to the changed lines.

Even if it also needed to change some of the surrounding lines for consistency (e.g.: maybe an entire (sub)declaration?), it would still be useful versus always changing the whole file.

This item seems related to #435 (comments to disable formatting on a subset of the file).