Re: speedup of modifying return values

[Taylan Kammer <taylanbayirli@gmail.com>]

Stefan Israelsson Tampe <stefan.itampe@gmail.com> writes:

> Hi all, I'm trying to make a python clone in guile. Currently the code is slow and one of  the reasons is the following,
>
> in my pythoon
>
> return 1,2
>
> returns a (values 1 2) in order to get python and scheme to interoperate. but for python if you use
>
> x = 1,2
>
> then x is the tupple '(1 2) and in guile it is 1. So therefore we wrap the result for
>
> x=f(10)
>
> as
> (set! x (call-with-values (lambda () (f x)) (case-lambda ((x) x) (x x))))
>
> This can be compiled to efficient bytecode but is not done so in guile. In stead a closure is created at each assignment site and creating ineficient code.
>
> Any ideas how to improve this (I don't want "return a,b" to mean (list a b) which is a quick solution
> if we want to just stay in python and not interoperate with scheme at all on this level.

Sounds like a fun project. :-)

Idea:

Make Python tuples a new data type, instead of multi-values.

The fact that they can be stored in a single storage location in Python
means that they are actually a data type, only special-handled for
automatic destructuring in some places...

Therefore, I would represent them as a record type under the hood.
Maybe one with a single field that contains a list or a vector.

I would then compile Python syntax that destructures tuples into
corresponding Guile code that destructures them also.

> Regards
> Stefan

Happy hacking,
Taylan