On Thu, May 21, 2009 at 11:01 AM, Ben Finney
Jeremiah Dodds firstname.lastname@example.org writes:
hmm, the 80-character convention does not stop me from unconsciously writing really complex list comprehensions, I just write them like so:
def foo(f, a, b, c): return [[((f(x,y) i, i) if i % 2 else 0) for i, x in enumerate(a) if f(y, x) == a + x] for y in [c(z) for z in range(a, ab+c, c)]]
not that that's really any better.
On the contrary, I find that much easier to grasp than the same statement on a single line. You have been required, by choosing to follow the 80-column limit, to choose points at which to break the line; and have responded by breaking it up into conceptually discrete chunks and indented to suggest the structure.
This example is, for me, a very convincing (anecdotal) demonstration of why an 80-column limit is a good constraint to follow.
Oh, yes - I consider it much easier to read than the single-line equivalent. What I meant by "not that that's really any better" was more along the lines of "that statement should probably be refactored". It's very rare that I run into a case where a convoluted list comprehension like that isn't better written some other way. Sometimes I end up with stuff like that when I've made incorrect assumptions while designing a program, etc.
But yeah, this is all anectodal evidence and personal taste, as Raymond points out.
Yet it's also more than that; to call it “personal taste” is to imply that it's nothing more than aesthetics. If that's all it were, I'd care far less for changes in convention.
I consider it rather more importantly a matter of software ergonomics, which should therefore not be changed unless there's good supporting evidence that the proposed change results in improvement.
I tend to agree. That's very well-said.