Am 04.03.2011 17:01, schrieb Magnus Lie Hetland:
I'm writing a collection with functionality for membership checking. I
thought it would be nice to use the "in" operator. In the docs for
std.collections I surmise that this is the standard way to go. From the
source code, I see there's no special opIn, but that it can be done with
the more general...

bool opBinary(string op)(T k) if (op == "in") {
...
}

Here T is, of course, a compile-time argument of the surrounding struct
or class.

So ... this is used in the the Phobos source in the DMD 2.052 distro (if
I'm not mistaken), but I can't get dmd 2.052 to accept it? I keep
getting the error message "Error: rvalue of in expression must be an
associative array, not Foo!(uint)".

I guess either that this is a recent feature -- I didn't see it
mentioned in Andrei's book -- and that my Phobos source is too recent
for my dmd ... or that I'm doing something wrong elsewhere in my code,
preventing the operator overloading to take force. Suggestions/solutions?-)


If you try to use it in the manner of `something in classWhichDefinesThisOpBinary` then it doesn't work because operator overloading normally overloads on the left operand (ie something). Use opBinaryRight(string op)(...) if(...) to get it working.

Mafi

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