KOS_OP_BRACKET_PROPER

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

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

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

• Use-case: Emitted by compile/bracket-proper, and by the quasiquote compiler for the segments of a [ ] form. The twin of PROPER: equivalent to BRACKET_CONS with an extra CONST bracket-nil on the stack, one instruction shorter.

Example: Build the bracket 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	BRACKET_PROPER	3	3	stack: […, [a b c]]