Lazy evaluation of function pointers.

[Ryan Frame via Digitalmars-d-learn]

Greetings.

The following code works:
void main() {
    passfunc(&func);
}

void passfunc(void function(string) f) {
    f("Hello");
}

void func(string str) {
    import std.stdio : writeln;
    writeln(str);
}

Now if I change passfunc's signature to "void passfunc(lazy void 
function(string) f)" I would get the compiler error "Delegate f 
() is not callable using argument types (string)". I can lazily 
pass a void function() -- it seems that there is only a problem 
when the function contains parameters.

The only difference should be when the pointer is evaluated, so 
why does lazy evaluation matter here?

Thank you for your time
--Ryan