Hi there,

I recently read the 'More Templates' chapter of Ali's book (<-- thanks for that ;) ).
At the section 'Named constraints', there were a definition like this:

template isUsable(T)
{
    enum isUsable = is ( typeof(
    {
        T obj;
        obj.call();
        obj.otherCall(1);
        obj.ye tAnotherCall();
    }() ) );
}

But at Phobos I always see definitions like this (std.range : isInputRange):

template isInputRange(R)
{
    enum bool isInputRange = is(typeof(
    (inout int = 0)
    {
        R r = R.init;     // can d
efine a range object
        if (r.empty) {}   // can test for empty
        r.popFront();     // can invoke popFront()
        auto h = r.front; // can get the front of the range
    }));
}


What does (inout int = 0) mean/affect here?
I created the same template for myself just without the (inout int = 0) and it worked (at least with a dummy struct)..


- Tim