Inconsistent null checks

[b4yuan]

lemon/src/scope.c

Line 74 in b1bb8a6

symbol = scope_add_symbol(lemon,

lemon/lib/os.c

Line 369 in b1bb8a6

tmobject = lobject_create(lemon, sizeof(struct ltmobject), ltmobject_method);

lemon/src/lemon.c

Line 531 in b1bb8a6

symbol = scope_add_symbol(lemon, lemon->l_global, name, SYMBOL_GLOBAL);

lemon/src/machine.c

Line 931 in b1bb8a6

frame = machine_peek_frame(lemon);

The functions called in these lines are consistently checked for null except in these instances. The lack of a null check could mask bugs.

[zhicheng]

Hi, good catch, I'm currently working on something else, sorry for really long wait of response(not login github for years). you're right about issues, but it's may wait a while to fix issues, if you can provide pull requests, would be really good. thank you.