I've been writing a lot of Perl lately. My current job is a good problem domain for Perl--lots of parsing--but that's not the point. The point is that I'm not hacking the Perl core any more, at least not often. I hardly work in C lately. It's all Perl and shell.
DAMN this is a fine language! Whenever I think of an abstraction, a rearrangement, a generalization, a feature, even sometimes just a vague concept
Of course, knowing how the core works is still remarkably useful. It removes the need for cargo cult or just-in-case programming practices; I don't have to worry whether something will really work the way I want if I know how it's implemented, down to the C function names. Whether this indicates something weak about Perl or is just a normal consequence of a complex system implemented on top of another system, I don't know. I suppose I should learn to hack the core of Python, or a JVM, so I can be sure....
Nah. I've got code to write. Now how can I factor out this expression here? Oh, that was easy.