What, again?

What, again?

Posted May 7, 2007 0:59 UTC (Mon) by ncm (subscriber, #165)
In reply to: What, again? by dcoutts
Parent article: The Rise of Functional Languages (Linux Journal)

No, I'm afraid you have completely missed the point.

In fact, in C++, the recipient of the object does not need to free it in a timely manner. Libraries do not rely on manual memory management everywhere. As I have noted elsewhere in this thread, it has been many years since I coded a "delete" statement. Where is this "cost of manual memory management" I am supposed to be paying everywhere? C++ coders don't pay any such cost.

In fact you can, in C++, abstract management of scarce resources (anyway). It may be necessary for the caller to know an expensive resource is contained, but not for the caller to explicitly call a "close" or "free" function to release it. In fact, most such objects' lifetimes are bounded by some scope, but (and this is important; stop and consider carefully) not typically the scope in which they were created or claimed. It is trivial to arrange for the equivalent of a close to happen automatically in C++, but it remains entirely impossible in any typical GC language, particularly including Lisp and all its descendants.

Let me repeat that: Turing-completeness notwithstanding, this common need in industrial programming is one that Lisp cannot address at all, as a direct result of a fundamental weakness in the core language design. That fundamental weakness cannot be resolved so long as CONS and GC remain in the core language. Other languages that have adopted Lisp's CONS and GC (or their equivalent) suffer the same weakness, whatever their other strengths.

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