Character escapes
Use the standard
to escape special characters,
in both string literals, and outside.
In general (outside string literals) a \
followed
by a non-letter character makes that character be treated as a letter.
E.g. \\1\+2 is a 3-character identifiers consisting of
the characters 1, +, and 2,
even if the languages normally otherwise doesn't allow identifiers
to start with digits or to contain +.
Letters don't need to be escaped, in either identifiers or names.
So we're free to use
followed by a letter for
other purposes, including the standard C string escapes.
I suggested at least the following:\
\xNNNN - A Unicode escape. Terminated by the first
character that is neither a digit or a letter.
If that character is a space, it is ignored.
Only a single space is ignored.
\n - A newline.
...
The string form of regular expressions should be compatible with this convention.