Indentation and optional delimiters

Steven D'Aprano steve at
Tue Feb 26 22:59:31 CET 2008

On Tue, 26 Feb 2008 05:36:57 -0800, bearophileHUGS wrote:

> So it can be invented a language
> (that may be slower than Python, but many tricks and a JIT may help to
> reduce this problem) where
> a = [1, 2, 3]
> b = a
> Makes b a copy-on-write copy of a, that is without reference semantics.

Usability for beginners is a good thing, but not at the expense of 
teaching them the right way to do things. Insisting on explicit requests 
before copying data is a *good* thing. If it's a gotcha for newbies, 
that's just a sign that newbies don't know the Right Way from the Wrong 
Way yet. The solution is to teach them, not to compromise on the Wrong 
Way. I don't want to write code where the following is possible:

a = [gigabytes of data]
b = a
f(a) # fast, no copying takes place
g(b) # also fast, no copying takes places
... more code here
... and pages later
... suddenly my code hits an unexpected performance drop
... as gigabytes of data get duplicated


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