On Wed, 15 Sep 2021 18:23:10 +0200, Mostowski Collapse wrote:
> I really wonder why my Python implementation is a factor 40 slower than
> my JavaScript implementation.
> Structurally its the same code.
>
> You can check yourself:
>
> Python Version:
> https://github.com/jburse/dogelog-moon/blob/main/devel/runtimepy/
machine.py
>
> JavaScript Version:
> https://github.com/jburse/dogelog-moon/blob/main/devel/runtime/
machine.js
>
> Its the same while, if-then-else, etc.. its the same classes Variable,
> Compound etc.. Maybe I could speed it up by some details. For example to
> create an array of length n, I use in Python:
>
> temp = [NotImplemented] * code[pos]
> pos += 1
>
> Whereas in JavaScript I use, also in exec_build2():
>
> temp = new Array(code[pos++]);
>
> So I hear Guido doesn't like ++. So in Python I use +=
> and a separate statement as a workaround. But otherwise,
> what about the creation of an array,
>
> is the the idiom [_] * _ slow? I am assuming its compiled away. Or does
> it really first create an array of size 1 and then enlarge it?
>
> Julio Di Egidio wrote:
<sniped due to top posting>
this is probably a string contender
i = 0
while i < len(term.args) - 1:
mark_term(term.args[i])
i += 1
term = term.args[i]
try replacing with something more pythonic
for index,term in enumerate(term.args):
mark_term(term.args[i])
& possibly go all the way to changing it into a comprehension
there are other similar anti patterns throughout this code.
any time you are manually keeping a counter as an index into a list,tupple
other iterable YOU ARE DOING IT WRONG!
Do not write javascript in python, write python
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