RE: Unicode fundamental character identity

Source separation for round-trip compatibility was a principle applied circa 1990 for compatibility with widely-used standards at that time.

Today, source separation is not a sufficient criterion for encoding distinctions in other legacy character sets. It can be provided as part of the evidence in a proposal, but other evidence would be required as for any new character proposal, in particular that a text element cannot be adequately represented using any existing character sequences and that there is a significant user community requiring public, plain-text interchange.


Peter

From: Sławomir Osipiuk <[email protected]>
Sent: February 3, 2025 10:36 AM
To: Peter Constable <[email protected]>; Peter Constable via Unicode <[email protected]>; [email protected]; James Kass <[email protected]>
Subject: Re: Unicode fundamental character identity

On Monday, 03 February 2025, 12:19:06 (-05:00), Peter Constable via Unicode wrote:
As stated previously, Unicode makes no guarantee of supporting source separation / round-trip compatibility with HP264x.

I'm honestly surprised by this. I always thought (because it was repeated so many times - must remember repetition does not equal truth) that round-trip compatibility with old character sets was a founding cornerstone of Unicode and so contrastive use (aka source separation) in an old charset would be persuasive evidence for inclusion.