a+++b parsing according to manual

[Doug Gwyn]

Certainly
	a+ ++b
cannot be parsed as
	a++ + b
since "+ +" is not a valid way of writing the ++ operator.
Spaces are indeed sometimes significant, which is why they SHOULD BE USED
when writing hard-to-parse-by-eye-and-maybe-by-compiler expressions.

Here is another good one for you; Ron Natalie reminded me today of the
fellow who used the C preprocessor to form composite tokens by something like
	#define	cat( a, b )	a/**/b
Of course this is SUPPOSED to work, but it depends on careful handling of
comments by the C preprocessor lexical analyzer.  (Consider what would
happen if a preliminary "comment stripping" pass were applied blindly.)