def rebuild_ast(instructions):
tags, exit = _extract_tags(instructions)
for idx, (op, var, val) in enumerate(instructions):
if op == Instruction.TAG:
yield (op, None, tags[idx + 1])
elif op in (Instruction.INC, Instruction.DEC):
yield (op, Instruction.num_to_var(var), str(val))
elif op == Instruction.JNZ:
yield (op, Instruction.num_to_var(var), tags.get(idx + 1, exit))
