Jose:
Unfortunately that text contains extra spaces which are not removed so that
is not a solution in general. Would ISO allow using `...` as multiline
string delimiter?
What is the use case for having significant spaces at the end of a
line *and* the need to see the text structure verbatim. This is
certaintly not the text of a programming language where only trailing
spaces are not significant except for continuation lines in strings.
The syntax of back quoted string (* 6.4.7 *) is defined already. So
if you want an extension using them you have to use that syntax and
maybe only recognize a subset of it as a valid extension. The syntax
is essentially the same of the double quoted list tokken (* 6.4.6 *)
and quoted token (* 6.4.2 *).