[Python-ideas] Make Python code read-only

[Victor Stinner]

2014-05-21 0:44 GMT+02:00 Greg Ewing <greg.ewing at canterbury.ac.nz>:
>> Optimizations possible when the code is read-only
>> =================================================
>>
>> * Inline calls to functions.
>>
>> * Replace calls to pure functions (without side effect) with the
>> result. For example, len("abc") can be replaced with 3.
>
> I'm skeptical about how much difference this would make.
> In most of the Python code I've seen, calls to module-level
> functions are relatively rare -- most calls are method
> calls.

If the class is read-only and has a __slots__ class attribute, methods
cannot be modified anymore. If you are able to get (compute) the type
of an object, you can optimize the call to the method.

Dummy example:
---
chars=[]
for ch in range(32, 126):
    chars.append(chr(ch))
print(''.join(chars))
---

Here you can guess that the type of chars in "chars.append" is list.
The list.append() method is well known (and it is read-only, even if
my global read-only mode is disabled, because list.append is a builtin
type).

You may inline the call in the body of the loop. Or you can at least
move the lookup of the append method out of the loop.

Victor