KOS_OP_MATCH_SPAN

• Style: EXTRA (LABEL, RAW, RAW): label, mark depth, cursor depth.

• Stack: [...] -> [..., span]; jump to a0 with nothing pushed when the span is empty.

• Semantics: Push the elements from the position of the mark at depth a1 to the cursor at depth a2: one element as MATCH_AT gives it, two or more as a tuple of them, a Datum per cell over a pair spine. Raises ValueError when the subject no longer holds the span.

• Compiler form: Emitted by the match compiler for a capture over a pattern whose width is not exactly one; the jump leaves the capture’s slot empty.