One microscopic point: [Guido]
... (if `.x` is unacceptable, it’s unclear why `^x` would be any better),
As Python's self-appointed spokesperson for the elderly, there's one very clear difference: a leading "." is - literally - one microscopic point, all but invisible. A leading caret is far easier to see, on a variety of devices and using a variety of fonts. Indeed, I missed the leading dot in ".x" in your email the first two times I read that sentence. But a caret is harder to type. So here's an off-the-wall idea: use an ellipsis. If you're still using a maximal-munch lexer, ellipsis followed by an identifier is currently a syntax error. "...x" is far easier to see than ".x', easier to type than "^x", and retains the mnemonic connection that "something is a named load pattern if and only if it has dots". "..." is also a mnemonic for "OK, here I want to match ... umm ... let me think ... I know! A fixed value." ;-)