KOS_OP_JUMP_OR_VAR

• Style: EXTRA (VAR, LABEL, NOARG, NOARG). Row = name, target pc.

• Stack: [...] -> [..., x] on the jump, [...] -> [...] on the fall-through. Read the value the name resolves to in the current frame’s namespace; if true, push it and jump to the target; if false, advance with nothing pushed. Raises NameError when the name is unbound.

• Invariants: Jump locality for target.

• Compiler form: Produced by ByteCodeProcessor.fuse_feeders absorbing a bare VAR load into the JUMP_OR it feeds. Lowers to JUMP_OR_FAST when the name has a fast slot.

Example: (or x default) in value position, both resolved by name.

index	opcode	arg	arg view	comment
0	JUMP_OR_VAR	0	(v#0 (‘x’), -> 2, 0, 0)	x true: push x, pc=2
1	VAR	1	1 (‘default’)	stack: […, default]
2	LABEL	–	–
3	RETURN	1	1