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Re: case mappings

This page is part of the web mail archives of SRFI 75 from before July 7th, 2015. The new archives for SRFI 75 contain all messages, not just those from before July 7th, 2015.

On 7/13/05, Matthew Flatt <mflatt@xxxxxxxxxxx> wrote:
> Although I agree that the 1-1 mapping is of limited use, my impression
> and experience is that it's still useful (if, for nothing else,
> interfacing to older code that uses a 1-1 mapping). So, pending further
> discussion, I will leave the character-casing operations in place.

Since we are proposing a new character based case mapping that
doesn't exist in Unicode, we need to be clear what the semantics are.

Specifically, unlike the R5RS ASCII based mapping

  (char=? (char-upcase c) (char-upcase (char-downcase c)))

is no longer a tautology (nor the reverse direction).

  (char-ci=? a b)

can no longer be defined as

  (char=? (char-upcase a) (char-upcase b))

or equivalently with char-downcase.


  (string-map char-upcase s)

is not the same as

  (string-upcase s)