Language change and code breaks

[phil hunt]

On Tue, 17 Jul 2001 13:13:36 GMT, Guido van Rossum <guido at python.org> wrote:
>philh at comuno.freeserve.co.uk (phil hunt) writes:
>
>> >I also don't want to fork the code base.  
>> 
>> Does that imply that you sare no longer interested in making 
>> radical changes to Python, such as case-insensitive identifiers
>> mentioned in CP4E?
>
>I still have the same end goal, but I believe there must be a way to
>obtain it without too much disturbance. 

Hmmm. I'm not sure about that, it feels to me like its opening up a
can of worms.

>Case-sensitivity, for
>example, may be a tool feature rather than a language feature, or it
>may be a user option or a langage-level choice. 

Say I write a module in the current (case-sensitive) Python. Then 
you write one in case-insensitive python. Your code calls one of my 
routines or variables; how does it get the case-sensitivity right?
Does it do so at run time or compile time? Compile time might
be difficult, for example if I have an object that dynamically
creates instance variables for itself. What if I have an object
ob with both ob.variable and ob.VARIABLE? What does your code
use when it resolves philsModule.ob.variable?

Case matching up at run-time is likely to make the language slower.

(One way I might consider fixing it would be to have the new
language explicitly say when it is dealing with old-python modules
and be case sensitive there; consider C++'s name mangling and the
extern keyword they used to link to C code.)

> (Not that I've
>figured out exactly how to do this, but TeachScheme makes this an
>option.)  Note that case-sensitivity is also controversial: the Alice
>folks found it a problem, but the VPython folks have not confirmed
>this (while they did confirm the integer division trap).

Who are the Alice people?



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