One professor of mine stated that Perl was a low-level language because the following code snippet for reading lines from a file was fairly slow compared to other languages:

    while ( my $line = <FILE> ) {
        # do something with $line
    }
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Well that's completely nuts, and so out of touch with reality. For a start, the underlying IO system of any decent OS will fetch the disk blocks of the file into memory in advance, especially for a sequential read. And the C library will then fetch the file in chunks of 4096 bytes (or so) at a time, and dole out the bytes line-by-line.

And regardless of any fanciness the OS and C library and Perl IO layers try to do, I/O IS SLOW! It doesn't matter if your snipper is sub-optimal, because its slowness will be lost in the noise. I really fail to see the professor's point: that snippet abstracts away the concepts of hard disks and buffers quite well in my opinion. I must be missing something.