[r6rs-discuss] [Formal] Scheme should not be changed to be case sensitive.

From: Peter Gavin <pgavin>
Date: Wed Nov 15 01:09:58 2006

On 11/14/06, John Cowan <cowan_at_ccil.org> wrote:
> Eli Barzilay scripsit:
>
> > * Unicode still changes. More frequently than RnRS even.
>
> It's *how* it changes that matters. Mostly it grows.
>

In addition, I would like to note that the Unicode standard is
versioned; it would definitely be possible to pin R6RS to a specific
version of Unicode.

I do, however, dislike the case folding of identifiers. Case folding
is not a reversible operation, and for instance, if an implementation
wants to print a backtrace after a failure of some sort, it would not
be possible to grep for the function name provided in the backtrace.
Also, the same program could refer to the same identifier using
different byte sequences, possibly of different lengths.

Another reason I disagree with case folding is that case folding is
not necessarily a fast operation, and it may slow down the reader
considerably. (Or it may not, I suppose it depends on the
implementation.)

One possible compromise, solely for the purpose of maintaining
backwards compatibility with R5RS: any character in the set of
uppercase Latin alphabetic characters (ASCII 0x41-0x5A) is
interchangeable with its lowercase version (ASCII 0x61-0x7A), and
vice-versa. Every other Unicode character is kept as-is, and no other
case manipulation occurs.

Pete
Received on Wed Nov 15 2006 - 01:09:51 UTC