[plt-scheme] re: case-sensitive reader by default

>> Other votes? 
>> 
I vote case-sensitive.


As Philippe's example shows, if you are shadowing variable names
and expecting one behavior or the other, things will be confusing.

But:
Consider a beginner who expects case-insensitive, even though the system 
is case-sensitive.
Presumably they're routinely sloppy their case,
even when not shadowing variable names.
Pretty soon, they'll get a nice, understandable error message,
will probably learn soon enough from non-shadowing situations
and they'll learn to be more careful.

The converse doesn't seem as likely:
if somebody expects case-sensitive when the system isn't,
they'll probably never get any symptoms until one day they start shadowing 
names, and then they're immediately tossed into the confusion zone w/o warning.


Separately, about experienced users:
Given that the string library functions are case-sensitive, 
and you have to explicitly add "-ci" to get the insensitive versions,
that seems to suggest a bias towards a case-sensitive world
(at least among library designers).