I can't resist putting on my surly curmudgeon hat to disagree about the value of "const".
In my experience, the hypothetical errors the compiler will catch for you are almost totally nonexistant, yet the work of complying with the A-R compilers nit-picking is a constant (heh!) drain or resources that could be spent on real problems. Possibly relevant questions: How many man hours have just been spent on adding const around the perl source? In that time, how many actual bugs have been detected and fixed by the compiler's const checks (I'm talking real bugs here, not merely new places where transitive closure of const forces the addition of more const modifiers to satisfy the compiler). Of course, my sour outlook is much worse because I deal with C++ most of the time where const is a far more virulent virus than it is in C. Take a look an any STL implementation sometime. There are two copies of just about every template definition. One for the const case, and one for the not const case. When compiler nit-picking forces you to duplicate all your code, you have a serious misfeature on your hands. How many more bugs are introduced because you forget and fix only one case of your template than are ever found because of the const checks? I know, I know, nobody agrees. But it is good to get on record so computer historians 1000 years from now will know there was one sane voice in the madness :-).
