Neal Becker schrieb:
>> No. Array references (x[i]) and attribute references (x.a) represent
>> "locations". Function calls represent values. This is no different
>> than the distinction between lvalues and rvalues in C.
>>
>
> Except this syntax is valid in c++ where X() is a constructor call:
>
> X(whatever) += 2; is (or can be) valid c++
That's actually the less-interesting case. You would have to overload
+= to make it work, right?
The more interesting case is when X is a function that returns a
reference:
int& X(int);
void foo(){
X(1) += 2;
}
int bar, foobar;
int& X(int t){
if(t) return bar;
return foobar;
}
Here, which variable gets incremented depends on whether the t
argument is true; no overloading of assignment comes into play.
The trick is that C++ has functions that *return* lvalues;
neither C nor Python has such things.
Regards,
Martin
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