What, again?

What, again?

Posted May 2, 2007 17:06 UTC (Wed) by dcoutts (subscriber, #5387)
In reply to: What, again? by ncm
Parent article: The Rise of Functional Languages (Linux Journal)

So you are exclusively using blocked scoped resources or smart pointers. With smart pointers you either are using ref counting or single owner semantics. Single owner is very limited, it doesn't allow you to build shared structures where there are multiple ways of reaching a value. If you're using ref counting it's not too bad, though you can't ever build cyclic data structures and you have to keep track of who is holding onto references or you get space & resource leaks. This last point is true of GC'ed languages too, forgetting that some object holds a reference to some resource causes space leaks.

In my experience, essentially all the times where we have to be concerned with use of a precious resource there are very clear bounds where the resource is needed. In almost all of these cases simple block scoping of the resource is sufficient. As you say there are some cases where we want more flexible techniques like pools but again these can be implemented in any language GC'd or not.

Sure the Java example where it does not let you do any manual resource management and only closes files via a finaliser is silly. All it needs is a .close() method or something and then in a nice functional language with cheap abstractions you don't even need to remember to call .close() as (like in my earlier example) you can write functions which encapsulate the resource usage patterns like allocate, use, release.

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