KOS_OP_PROPER

• Style: COUNT. Arg = number of element values on stack.

• Stack: [..., e_0, ..., e_{count-1}] → [..., result] where result is the proper list (e_0 e_1 ... e_{count-1}). nil is implicitly appended as the tail. count 0 → push nil directly.

• Invariants: Each e_i may be any Python object; none need be a pair.

• Use-case: Emitted by the quasiquote compiler for segments of non-splice elements. Equivalent to CONS with an extra CONST nil on the stack, but more compact: saves one instruction per list.

Example: Build the proper list (a b c) from three constants.

index	opcode	arg	arg view	comment
0	CONST	0	0 (sym a)	stack: […, a]
1	CONST	1	1 (sym b)	stack: […, a, b]
2	CONST	2	2 (sym c)	stack: […, a, b, c]
3	PROPER	3	3	stack: […, (a b c)]