[tom_]

I've never liked this sort of thing in code, because as things stand they're a bit of a faff to type, and some tools don't support them very well. But it's a shame, because there's loads of types of quote mark and bracket in Unicode, not just the ``...''-type pair commonly used in English. So you could use one type for string delimiters and then use the other types, unescaped, in the string itself.

(The Unicode quotes also mostly come in matching pairs, so, for good or for ill, they'd in principle be nestable.)