Returns, as if by return-from, from the block named nil.
→ →1
(block nil (return (values 1 2)) 3)
→1 2
(block nil (block alpha (return 1) 2))
→1
(block alpha (block nil (return 1)) 2)
→2
(block nil (block nil (return 1) 2))
→1
None.
None.
(return) ≡ (return-from nil) (return form) ≡ (return-from nil form)
The implicit blocks established by macros such as do are often named nil, so that return can be used to exit from such forms.