From: "Moore, Paul" Paul.Moore@atosorigin.com
From: Samuele Pedroni [mailto:firstname.lastname@example.org]
the first candidate would be a generalization of 'class' (although that make it redundant with 'class' and meta-classes) so that
KEYW-TO-BE kind name [ '(' expr,... ')' ] [ maybe  extended syntax ]: suite
would be equivalent to
name = kind(name-as-string,(expr,...),dict-populated-executing-suite)
[fixed up to exclude the docstring, as per the followup message]
an alternative (if parseable, I have not fully thought about that) would be to leave out the KEYW-TO-BE and try to parse directly
kind name [ '(' expr,... ')' ] [ maybe  extended syntax ]:
where kind could be any general expr or better only a qualified name that are NOT keywords, so we would possible have:
property foo: <suite>
interface.interface I(J,K): <suite>
all working as specified like 'class' and with its scope rules.
Control flow statements would still have to be added to the language one by one (I find that ok and pythonic). Also because specifying and implementing implicit thunk with proper scoping and non-local return etc does not (to me) seem worth the complication.
About extending or generalizing function 'def' beyond  extended syntax, I don't see a compelling case.