scott@Apple.COM (scott douglass) (12/18/90)
Why does the ARM (in section 5) allow some non-traditional
(w.r.t. ANSI-C) lvalues?
For instance the following statements are legal in C++, but not C:
(++i) = 2; // ARM 5.3.1
(i += 3) = 5; // ARM 5.17
But the following is not:
(i++) = 7; // ARM 5.2.5
And the following are not explicitly specified:
(-i) = 11; // ARM 5.3
(i + 13) = 17; // ARM 5.7
The usefulness of such constructs seems limited. (My guess
is that the intent was to allow various user defined operator
overloadings to return lvalues. This is not a good reason
since section 5 explicitly does not apply to overloaded
operators (the commentary even reiterates the point).)
Hopefully the standard will explicitly state the lvalue-ness
of all expressions.