You seem to have taken particular exception because you think I made no real case, but argued:

... on the basis of: commenting is so obviously good, that not commenting can *only* be the product of laziness and indifference; which is absolutely not the case for many of us that prefer minimal commenting.

Well... what I thought I'd done was to describe in broad terms what I consider to be the attributes of good commenting, and then to enumerate what I think are some of the benefits. I fail to see how that is starting from a position of "commenting is so obviously good", far less jump from there to an accusation of "laziness and indifference". I feel you've misrepresented what I said... but, hey ho, it's an imperfect world.

I agree that there is such a thing as excessive and pointless commenting -- which is made-work both for the original author and for later modifiers. In my assembler days I would despair of programmers who thought that every instruction required a comment saying what it was.

I'm not sure whether you are arguing for no comments at all, or whether the question is the degree and type of comments ? If the second, then I'd be interested to hear what you think represents "good" commentary.

However, you asked for an example. OK. I posted this some time ago. I haven't constructed it as a text book example of good commenting -- in any case, like most forms of writing the question is: "who is the audience ?". Alternatively, I can offer ensure.pm. I look forward to seeing them torn to shreds :-) [Looking back at the posting, there is quite a bit of background -- if you just want to look at the module, see here.]

I will also give an example of where, IMO, there is a shortage of comments. This is from numeric.c in the Perl 5.10.0 source.

what I thought I'd done was to describe in broad terms what I consider to be the attributes of good commenting,

Your opening line is:

"It is indeed a sad state of affairs when programmers fail to properly comment as they write code."

And that sets the tone for the entire post.

For the rest. When I encounter modules that contain that much verbiage I often just delete it without reading it.

Especially when I encounter comments like

  # Reverse sort the set and partitions and insert sums
[download]

To "document":

  @$rs = reverse sort numerically @$rs ;
  @a   = ($sa, reverse sort numerically @a) ;
  @b   = ($sb, reverse sort numerically @b) ;
[download]

• Reverse: This keyword precedes all three sorts.

  It is redundant.

• sort: as is this.
• the set: if @$rs was @$set, this word becomes redundant.
• and partitons: Ditto these, if @a and @b where @partA and @partB.

  Especially if the sub were called partitionShuffled() rather than hack_C.

• And insert sums: Ditto if $sa and $sb where $sumA & $sumB.

Three lines of verbiage (including 2 blanks) mostly redundant. And completely redundant if the documentation is placed in the only verifiable content of the file--the code.

And

  # Done -- return partitins in required order
[download]

to "document"

  if ($a[0] >= $b[0]) { return (\@a, \@b) ; }
                 else { return (\@b, \@a) ; } ;
} ;
[download]

• Done --: The end of the subroutine and your done. No shit Sherlock!
• return: And your going to return something. Cool.

  The fact that you use return in the code (twice) is a pretty clear clue.

• partitins: @partA & partB would be so much better.
• in required order: Required for what? By whom?

  You mean partition A then partition B if the sum of A is greater or equal to the sum of B. Or vice versa otherwise.

• (And what's with that floating semicolon after the subroutine?)

Again, mostly redundant, with the code being far clearer than the "documentation".

And the whole lot would be clearer still (and far more efficient to boot), written as:

    # Sort the callers array in-place
    @$set = sort{ $b<=>$a } @$set;

    return $sumA >= $sumB 
        ? ([ $sumA, sort{ $b<=>$a } @partA ], [ $sumB, sort{ $b<=>$a }
+ @partB ])
        : ([ $sumB, sort{ $b<=>$a } @partB ], [ $sumA, sort{ $b<=>$a }
+ @partA ])
    ;
}
[download]

---

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

"Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."

Thanks for the comments.

It appears there is little common ground on which to base a discussion, but since you picked out two examples, I'll address those briefly, and then not waste any more of the monks' time.

For me, the writing of comments is part of the thinking process. The comments you commented on were (if memory serves) written before the code, as I was sketching out what needed to be done. I agree that comments that do no more than repeat what the code says are not only redundant, but can simply be clutter (except where the code is particularly tricky) -- for me the key is to concentrate on the "why". Though I do find it useful to use comments to point up the stages that a block of code goes through.

The first comment you picked out:

  # Reverse sort the set and partitions and insert sums
[download]

served several purposes: (a) it was a stage in the subroutine; (b) the algorithm used depends on stuff being reverse sorted, this is key to understanding what is going on; (c) it's doing something a little tricky: in the resulting array entry 0 is not the same as the other entries, it's the sum of those entries. While I was writing it, I thought about all this... I suppose I could have written a longer comment to emphasise the key points...

The other comment you picked out:

  # Done -- return partitins in required order
[download]

(sorry about the spellin error)... well, yes, it's not the most significant of the comments in a 2,800-odd line module. Again, the subroutine was broken into stages, so this also serves as the end of the previous stage. The order in which the partitions are returned is key -- the caller can (and does) depend on this.

As it happens, there are three similar subroutines, with the same general shape, and the comments emphasise that. You've commented on the smallest of the three, where there is less to comment on.