[Python-ideas] Adding "Typed" collections/iterators to Python

Terry Reedy tjreedy at udel.edu
Wed Dec 21 00:01:26 CET 2011

On 12/20/2011 1:50 PM, Nathan Rice wrote:

> I put a module called "elementwise" on pypi
> (http://pypi.python.org/pypi/elementwise/0.111220) that implements my
> idea of what a nice broadcast proxy should do.

I downloaded and took a brief look. I hope to get back to it later.

2.) there are serious dragons in
> how python handles complex inheritance graphs that result in
> "object.__new__() takes no parameters", despite not having any builtin
> bases and having no base class overriding __new__ or __init__

Best not to use object as the apex of multiple inheritance.

> Because "typed" is sort of a dirty word in the python community,

Not exactly true, and unnecessarily combative. More true is that 
careless use of 'typed' has gotten tiresome. Python is strongly 
dynamically typed. But people occasionally post -- again the same day 
you posted to python list -- that Python is weakly typed. I am tired of 
explaining that 'typed' is not synonymous with 'statically typed'.

Or consider your subject line. Python collections are typed both as to 
collection object and the contents. Python has narrow-content typed 
sequences. So just saying you want 'typed collections' does not say 
anything. We already have them. We even have propagation of 
narrow-content typing for operations on bytes and strings.

But we do not have anything similar for numbers or user classes. And 
that might be worthwhile. So your subject seems more like 'adding 
generic narrowly typed sequences to Python'.

Terry Jan Reedy

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