Any IDE could deal with that. The IDE could display the operator iv a
special font, colour, size, or with one of the Unicode symbols.
You might not even need to key it differently. The IDE might be smart
enough to discriminate.
This is equivalent to "IDEs should have special syntax highlighting
for user-defined operators" for IDE users, while gratuitously
penalizing those that don't use IDEs.
May as well just suggest special syntax highlighting. There's no
reason why syntax highlighting has to be limited to color, even -- it
could involve fonts and special symbols, e.g. Arial bold* on the names
of static finals versus Courier on keywords, or use of a circled plus
for a user-defined plus operation.
* Modified to be monospaced, of course.
But no suggestion that will cause non-IDE users to reach for alt
+numpad or the CharMap applet every five LOC is ever going to pass
muster.
(Some people at work use NetBeans. It seems to use italics on static
method and field names. It uses italics on something. It definitely
distinguishes between primitive and non-primitive types, since it
highlights primitive type names the same as other keywords; Eclipse,
which I use, does likewise. Primitive and non-primitive operators
being similarly distinguished only seems natural if ever such a
feature gets introduced into Java.)