Re: [apps-discuss] Retroactive application of draft-ietf-appsawg-uri-scheme-reg - comprehensive review

[Barry Leiba <[e-mail]>]

> No scheme can prohibit fragments. They are not part of the scheme's syntax.

We continue to have a confusion between syntax and semantics here.

I absolutely agree that no scheme can say that fragments are
syntactically invalid, because the schemes do not control the syntax
of a URI.

But a scheme can certainly say that fragments make no semantic sense
within that scheme, and that if a URIs uses that scheme and contains a
fragment, it is not a well formed URI within that scheme.

It's rather like saying that English words are composed of characters
from the set "abcdefghijklmnopqrstuvwxyz", and, therefore, the string
"qwx" is a valid piece of an English word (syntax)... but that, in
fact, no valid English words contain "qwx" (semantics).

That's not a layering violation at all -- it has to be up to the
scheme to say what the semantic meaning of a fragment is within that
scheme, or whether fragments have any meaning at all.

Barry