>>>>> f.func_annotations
>> {'x': 1}
>
> Very cool! I agree that Phillip's idea for simplification is worth a
> try. We're generally not too concerned over the cost of function
> declarations since they typically execute only once per program. As
> long as it's really cheap when no annotations are present (which would
> suggest that func_annotations should be None in that case since an
> empty dict is kind of expensive, at least in memory).
>
>
func_annotations could create the empty dict just in time.
Building the annotations dict in bytecode actually takes slightly
more C code
and quite a bit more bytecode. Maybe using dict(zip(<tuple from
co_consts>, <values from stack>)) would
be more efficient. I'll probably keep both the MAKE_FUNCTION change
and the bytecode version for a while.
The next step is changing the syntax for nested parameters, eg
def f((x:1, y:2))
>>> dis.dis(compile("def f(x:1, y:2=3, z=4)->5:pass", "<str>", "exec"))
1 0 LOAD_CONST 0 (3)
3 LOAD_CONST 1 (4)
6 LOAD_CONST 2 (<code object f at
0xb7ec70b0, file "<str>", line 1>)
9 MAKE_FUNCTION 2
12 DUP_TOP
13 BUILD_MAP 0
16 DUP_TOP
17 LOAD_CONST 3 (1)
20 ROT_TWO
21 LOAD_CONST 4 ('x')
24 STORE_SUBSCR
25 DUP_TOP
26 LOAD_CONST 5 (2)
29 ROT_TWO
30 LOAD_CONST 6 ('y')
33 STORE_SUBSCR
34 ROT_TWO
35 STORE_ATTR 0 (func_annotations)
38 DUP_TOP
39 LOAD_CONST 7 (5)
42 ROT_TWO
43 STORE_ATTR 1 (func_returns)
46 STORE_NAME 2 (f)
49 LOAD_CONST 8 (None)
52 RETURN_VALUE
>>> dis.dis(compile("def f(x:1, y:2=3, z=4)->5:pass", "<str>", "exec"))
>>>
1 0 LOAD_CONST 0 (3) # default for y
3 LOAD_CONST 1 (4) # default
for z
6 LOAD_CONST 2 (1) # annotation
for x
9 LOAD_CONST 3 (2) # annotation
for y
12 LOAD_CONST 4 (6) # bitmask for
annotations... 0b110
15 LOAD_CONST 5 (5) # func_returns
18 LOAD_CONST 6 (<code object f at
0xb7f08848, file "<str>", line 1>)
21 MAKE_FUNCTION 49154 # numdefaults(2) +
kwdefaults(0) << 8 + has_annotations(1) << 14 + has_returns(1) << 15
24 STORE_NAME 0 (f)
27 LOAD_CONST 7 (None)
30 RETURN_VALUE
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