What on Earth is so great about strong typing that I have to have it?

I've usually been told "strong typing: good!" with no rationale. Occasionally, I'm told "strong typing helps prevent programmer error", with no explanation of how it prevents errors. (Okay, so it stops me from adding a string and an int. If I was adding strings and ints and expecting to get something useful, I have deeper problems than weak typing.)

It occurs to me that a C-like "suggested typing" system encodes some information about a variable's domain. For instance, declaring int foo; says some things about foo: it measures a discrete value, for one. Chances are, the more information you give the person reading your code, the better; on the other hand, I can't think of any situation where this would be more useful than a proper variable name (my $line_count;).

About the only advantage I can see in a stronger typing system than Perl's is the ability to align data in memory very precisely, which is useful when you're talking directly to hardware. I don't know of anyone doing that in Perl, though, and it doesn't require a strongly typed language: C does it rather well.

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:wq