On 24/11/2015 20:54, Antoon Pardon wrote:
Op 24-11-15 om 20:15 schreef Ian Kelly:
But no matter what you want to call it. The dis module shows that
-42 is treated in exactly the same way as 42, which is treated
exactly the same way as () or as (5, 8, 13) which is treated
differently from [] or [5, 8, 13].
This is an implementation detail. The compiler would also be free to
compile -42 into byte code as the negation of the constant 42. That 42
is a literal, on the other hand, is part of the language
specification.
I think you are picking nits. Sure the byte code could compile -42 into
a byte code for 42 and a negation. Just as it could compile 42 into byte
code for adding 32, 8 and 2.
The point is, that the reverse isn't true. It couldn't compile [5, 8, 13]
into a LOAD_CONST.
I think it can, with a couple of extra instructions:
LOAD_GLOBAL 0 (list)
LOAD_CONST 1 ((5, 8, 13))
CALL_FUNCTION
ie. by converting a tuple to a list, but it can also be done with a
special byte-code. The effect is a that a constant list can be
constructed without having to evalate each element at runtime, which I
assume would be less efficient if the list is big enough (perhaps not
for just 3 elements).
--
Bartc
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