[LLVMdev] Iterator protocols

[Marc B. Reynolds]

> So the question is, what's the trade-off. In most languages that support 
> exceptions, you tend to think of exceptions as expensive operations that 
> should only be thrown if something truly "exceptional" happens. 

Certainly the vast majority of cases, but is it also reasonable to write a
method that will likely or always throw an exception, but cheaper to setup,
unwind and tear-down the exception than to litter a computational expensive
routine with explicit end-condition testing. 

> OTOH, the Java case is also made worse by the fact that a large part of
> the time you'll be using the more expensive interface dispatching,
> rather than simple vtable dispatching.

What I've seen is that when runtime compiling: most 'invokeinterface' calls
can
be converted into direct vtable dispatches, specifically when the type of
the
object in question is a class (as opposed to an interface). And in the
remaining
cases, when the type is an interface, the methods tend to be short and
suitable
for inlining. (mileage may vary)