KOS_OP_MATCH_STORE

• Style: EXTRA (RAW, RAW, RAW, CONST): mark depth, slot index, cursor depth, names tuple.

• Stack: [..., v] -> [...]; cannot miss.

• Semantics: Pop v into slot a1 of the mark at depth a0, replacing what the slot held. When the cursor at depth a2 walks a pair spine, a Datum v, and each Datum in a tuple v, takes the name a3[a1] as its binding; a Datum from a tuple, list or single value is stored unchanged. A cursor depth a2 of 0 names no cursor: v was tested where it lay, and is stored unchanged.

• Invariants: a3 is a tuple with an entry at a1; Code construction raises ValueError otherwise. An index outside the mark’s slots raises SystemError.

• Compiler form: Emitted by the match compiler for each capture, with the names of the capture’s scope, but for the root captures of a match arm, which are stored into their variables.