KOS_OP_MATCH_TAIL

• Style: EXTRA (LABEL, RAW, RAW, RAW): label, cursor depth, suffix width, minimum.

• Stack: [...] -> [..., span]; jump to a0 with nothing pushed on a miss.

• Semantics: Take the elements left at the cursor at depth a1 but the last a2, push them as a span, and advance the cursor past them. A miss when fewer than a2 elements remain or the span holds fewer than a3. Over a tuple, list or other sequence the span is a tuple of the items; over a single value, a one-element tuple of the value or the empty tuple. Over a pair spine it is a Datum over the rest of the spine when the span runs to the spine’s end, a Datum over the spine’s terminator when the span is empty, and otherwise a tuple of a Datum per cell; a spine cut inside the span raises ValueError.

• Compiler form: Emitted by the match compiler for a rest pattern (*: rest, REST).