Re: M4 syntax $11 vs. ${11}

[Paul Eggert]

Eric Blake <address@hidden> writes:

> +  /* This warning must not kill m4 -E, or it will break autoconf.  */
> +  if (text && strstr (text, "${"))
> +    M4ERROR ((0, 0, "Warning: raw `${' in defn of %s will change semantics",
> +           name));

This warning will generate a lot of false positives, right?
Most of the time, a stray ${ in an M4 file won't be followed
by a series of digits and then a }.  So it will be treated
as itself (for backward compatibility).

I suggest having the warning complain only about ${X}, where X is a
string of one or more ASCII digits.  It shouldn't complain about
other usages of ${.  If you do it that way, you shouldn't need
to change either Autoconf or Automake.