Question about Perl5 extended UTF-8 design

Richard Wordingham richard.wordingham at
Fri Nov 6 14:32:20 CST 2015

On Thu, 05 Nov 2015 13:41:42 -0700
"Doug Ewell" <doug at> wrote:

> Richard Wordingham wrote:
> > No-one's claiming it is for a Unicode Transformation Format (UTF).
> Then they ought not to call it "UTF-8" or "extended" or "modified"
> UTF-8, or anything of the sort, even if the bit-shifting algorithm is
> based on UTF-8.

> "UTF-8 encoding form" is defined as a mapping of Unicode scalar values
> -- not arbitrary integers -- onto byte sequences. [D92]

If it extends the mapping of Unicode scalar values *into* byte
sequences, then it's an extension.  A non-trivial extension of a
mapping of scalar values has to have a larger domain.

I'm assuming that 'UTF-8' and 'UTF' are not registered trademarks.


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