ANN: Dogelog Runtime, Prolog to the Moon (2021)

[Mostowski Collapse]

And how do you iterate over the first n-1 elements
of a list with n elements? This is what my code does:

i = 0
while i < len(term.args) - 1:
____mark_term(term.args[i])
____i += 1
term = term.args[i] 

You can try yourself:

% python3
>>> foo = ["a", "b", "c"]
>>> i = 0
>>> while i < len(foo) - 1:
...     print("mark_term", foo[i])
...     i += 1
... 
mark_term a
mark_term b
>>> foo = foo[i]
>>> foo
'c'

alister schrieb am Mittwoch, 15. September 2021 um 20:41:12 UTC+2:
> On Wed, 15 Sep 2021 11:31:48 -0700, Mostowski Collapse wrote: 
> 
> > There is a further problem with this: 
> > 
> >> for i,term in enumerate(term.args): 
> >> ____mark_term(term.args[i]) 
> > 
> > It should read: 
> > 
> > for i,help in enumerate(term.args): 
> > ____mark_term(help) 
> > 
> > But then i isn't need.
> even Better (i had only skimmed the code as I was certain I would find 
> this, it is probably the No. 1 thing new python programmers get wrong 
> if your example is correct the it can be simplified even further to 
> 
> for help in term.args: 
> mark_term(help) 
> 
> & if help does not get used after this loop then a comprehension is even 
> better 
> _ == [mark_term(help) for help in term.args] 
> 
> 
> the underscore character is python convention for an unneeded place- 
> holder variable.
> > 
> > Mostowski Collapse schrieb am Mittwoch, 15. September 2021 um 20:22:50 
> > UTC+2: 
> >> Do you mean, replace this: 
> >> i = 0 while i < len(term.args) - 1: 
> >> ____mark_term(term.args[i]) 
> >> ____i += 1 term = term.args[i] 
> >> 
> >> By this: 
> >> 
> >> for i,term in enumerate(term.args): 
> >> ____mark_term(term.args[i]) 
> >> 
> >> This wouldn't be correct anymore. The recursive call is only for the 
> >> arguments except for the last one one. 
> >> alister schrieb am Mittwoch, 15. September 2021 um 20:17:23 UTC+2: 
> >> > 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 
> >> > 
> >> > 
> >> > 
> >> > -- 
> >> > Two percent of zero is almost nothing. 
> >> > 
> >> > 
> >> > 
> >> > 
> >> > -- 
> >> > Whoever dies with the most toys wins.
> -- 
> Pie are not square. Pie are round. Cornbread are square.