Early binding as an option

Chris Angelico rosuav at gmail.com
Tue Aug 2 18:55:30 CEST 2011


As I understand it, Python exclusively late-binds names; when you
define a function, nothing is ever pre-bound. This allows a huge
amount of flexibility (letting you "reach into" someone else's
function and change its behaviour), but it's flexibility that most
programs use seldom if at all.

First off: Is there any way to request/cause some names to be bound
early? and secondly, should there be?

Argument against: Late binding is a Good Thing, and having some things
bound early would be confusing.

Argument in favour: Efficiency is also a Good Thing, and with staples
like 'len', it's unlikely anyone will want to change them - yet the
interpreter still has to do a namespace lookup every time.

I would want the end programmer to have the ultimate power here (not
the module designer). Something along the lines of: This global name
will never change, so don't bother looking it up every time.

As an example of this difference, Pike uses early binding for some
things; when I did the perfect numbers testing in the other thread
(discussion thread, not thread of execution!), Pike performed
significantly better; I believe this is in part due to the formal
declarations of variables, and the consequential simplification of
local code, although since there are no globals being looked up here,
there's little to be gained from those.

Is this the realm of JIT compilation, or can it be done in regular CPython?

Chris Angelico



More information about the Python-list mailing list