The interpolation is most useful if you had something like this robin
some_template = """
This is a really long string with ${interpolatedvar}.
Making a bunch of concatenates is not desirable because we want ${var1} to be interchangeable
and also not make our ${var2} completely useless
"""
But it can also be used for trivial cases as well as in the original post.
Also this @OP it is probably possible and you just need an escape on either the $ or {. here is the docs: http://docs.groovy-lang.org/2.5.1/html/documentation/#_string_interpolation
The reasoning for the escape is probably due to the parser already having interpolated or escaped it.