Thanks Isaiah. Reading through that history was fun and informative :)
In this <https://github.com/JuliaLang/julia/issues/2301> discussion, Stefan
initially suggested we can use interp_parse to help with interpolation with
non-standard string literals, but by the end of the discussion,
interp_parse was removed from Base. However, I think we still need that if
we want interpolation to work with non-standard string literals. Removing
it form Base probably largely explains why I've seen similar functionality
rewritten in multiple places. For my purposes, I just resurrected
interp_parse (with minor mods to get it to work in 0.4.2). It is
interesting to learn how it works :)
