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

[Peter J. Holzer]

On 2021-09-20 04:33:39 +1000, Chris Angelico wrote:
> On Mon, Sep 20, 2021 at 3:19 AM Mostowski Collapse <janburse at fastmail.fm> wrote:
> > Question to Chris Angelico: If I stay with my
> > sweep_trail(), which is the periodically scanning,
> > I can use a single linked list.
> >
> > On the other hand if I would use the trigger
> > from Python, I possibly would need a double linked
> > list, to remove an element.
> >
> > Chris Angelico, is there a third option, that I have
> > overlooked? Single linked list uses less space
> > than double linked list, this why I go with scan.
> >
> 
> I don't know. I don't understand your code well enough to offer advice
> like that, because *your code is too complicated* and not nearly clear
> enough.
> 
> But however it is that you're doing things, the best way is almost
> always to directly refer to objects. Don't fiddle around with creating
> your own concept of a doubly-linked list and a set of objects; just
> refer directly to the objects.

And almost certainly: Just use the builtin list type if you need a list.
Don't build one yourself.


> Let Python be Python, don't try to build your own language on top of
> it.

Well, he's writing a Prolog interpreter, so building his own language on
top of Python is sort of the point. I think a better way to put it is
"Don't try to write Python as if it was C". A C operation may be
compiled to a single machine instruction which is executed in a fraction
of a nanosecond. A Python instruction (in CPython) always includes at
least the interpreter overhead and often several method lookups and method
calls. You want to amortize that overhead over as much work as possible.

        hp

-- 
   _  | Peter J. Holzer    | Story must make more sense than reality.
|_|_) |                    |
| |   | hjp at hjp.at         |    -- Charles Stross, "Creative writing
__/   | http://www.hjp.at/ |       challenge!"
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