[conaclos]

I like the idea of repeating the delimiter on every line. However `//` looks like a comment to me. I could simply choose double quote:

    const still_raw =
        "const raw =
        "    "Roses are red
        "    "  Violets are blue,
        "    "Sugar is sweet
        "    "  And so are you.
        "    "
        ";
        "
    ;

This cannot be confused with a string literal because a string literal cannot contain newline feeds.

[flexagoon]

What if you have something like

    const raw =
        "He said "Hello"
        "to me
    ;

Wouldn't that be a mess to parse? How would you know that "He said " is not a string literal and that you have to continue parsing it as a multiline string? How would you distinguish an unclosed string literal from a multiline string?