Clarification of directional mode (SCP)
From ECMA-48 it is not completely clear whether this is something like RLO or more like a preset paragraph embedding level. As RLO control exists in Unicode, the latter would be more useful, so that assumption makes more sense. Mintty experimentally implements as follows:
- SCP 0 selects mintty default behaviour; this means each line is handled like a separate paragraph, UBA rule P2 is applied initially.
- SCP 1 invokes the bidi algorithm with paragraph embedding level 0, rule P2 is skipped.
- SCP 2 invokes the bidi algorithm with paragraph embedding level 1, rule P2 is skipped.