The Cost of Dynamism (was Re: Pyhon 2.x or 3.x, which is faster?)

[Ned Batchelder]

On Thursday, March 24, 2016 at 2:03:58 PM UTC-4, BartC wrote:
> On 24/03/2016 17:13, Ned Batchelder wrote:
> > On Thursday, March 24, 2016 at 12:12:55 PM UTC-4, BartC wrote:
> >> On 24/03/2016 15:30, Ned Batchelder wrote:
> >>> On Thursday, March 24, 2016 at 9:51:11 AM UTC-4, Steven D'Aprano wrote:
> >>>> You know what is missing from this conversation?
> >>>>
> >>>> For one of Bart's critics to actually show faster code.
> >>>>
> >>>> There's plenty of people telling him off for writing unpythonic and slow
> >>>> code, but I haven't seen anyone actually demonstrating that Python is
> >>>> faster than his results show.
> >>>
> >>> As I mentioned before, I'm happy to explain the fuller Python way to
> >>> write code, but I don't think Bart wants to learn it, because he is
> >>> focused on a different goal than, "write real Python code the best
> >>> possible way."
> >>>
> >>> Here, for example, is a real lexer for JavaScript that I wrote:
> >>> https://bitbucket.org/ned/jslex/src
> >>>
> >>
> >> Thanks for that.
> >>
> >> I don't have any JS to throw at it, but it seems happy with any bits of
> >> source code or even just text.
> >>
> >> Using your short driver program (with the prints commented out), and
> >> tested with 'bible.txt' as input (ie. mostly English words), then your
> >> JS lexer was roughly half the speed of the Python version I linked to
> >> last week (with the if-elif chains and working with strings).
> >
> > I have tried to find your code, but cannot find in the forest of this thread.
> > Can you provide a link to it online?  I would be very interested to understand
> > the difference in performance.
> 
> This the version I used today:
> 
> http://pastebin.com/dtM8WnFZ
> 

Thanks. It is faster than mine. The lesson I learned is, if you (I) make
regexes too fancy, they are slower than the low-tech way. :)  I suspect
there is a way to use the re module more efficiently, but I don't have
the time at the moment to figure out how.

--Ned.