Hacker News Reader

Comment by h2s | Hacker News Reader

I can't agree with you emphatically enough about this. Cargo cult commenting is one of the easiest ways to damage the readability of a codebase.

Comments should be an edge-case solution for explaining unusual quirks, not the go-to approach for explaining the entire codebase. Using comments to explain what the code is up to is like using exceptions for flow of control. A large proportion of the comments I see should actually be function or method names for a more well factored version of the block of code that follows.

View on HN

This point gets brought up a lot, but I'm not going to complain at all. In fact, just 5-6 months ago I used to be one of those programmers who would do

    # gets the xml
    def get_xml():

It took comments like this to help me realize just how silly the whole thing was. Now I write as much self-documenting code as I can, but comment as needed.

Sure.

Comment should be "why I did this", and code should be "how I did this", some people just write in "what did I do" and walk away thought they have comment

Code took from a project I'm working with:

  #End of package

I generally become aware that I should leave a comment whenever I write something that is less than trivial (but exactly less than trivial) to write/understand. Longish list comprehension? Summarize what it does. Nested function calls? Summarize why. Etc.

> Comment should be "why I did this", and code should be "how I did this"

the problem starts when the 'why' doesn't match the 'how'...which one is "correct"?

"A large proportion of the comments I see should actually be function or method names for a more well factored version of the block of code that follows."

I share the same experience.

This may be a valid argument for modern languages like Ruby or Python. For 90s' coding standards however comments are even MORE important than the code itself. For Assembly and C programming and for low level graphics and physics algorithms proper naming of variables and functions are never enough for readable code.

I agree that comments should not be the "go-to approach for explaining the entire codebase." I hope you didn't think I was insinuating that in my comment. I was only trying to illustrate that in the absence of clear code, which many developers are guilty of sometimes, comments can be very helpful.

Nah I didn't think that at all, it was clear from the way you said "minimal commenting". I just have an axe to grind when it comes to comments of the form

    // assign the integer value 10 to the variable x
    x = 10

What's really annoying is that most of the time you see this kind of comment there is no explanation why 10 was chosen.

And that's what comments really need to do: tell 'why.'

http://xkcd.com/221/

That's why you should use constants. Still self documenting without the need for comments (usually).

    const TEN = 12;

    #define true false

In our embedded systems class we were required to define all of our constants, just to add another level of description to operations. It definitely helped to navigate spaghetti code.

At least it's better than:

    // set the variable x to 10
    x = 12;

  sFile = "filename.xml";

then later

  sFile = File.ReadAllText("filename.xml");

I think you've forgotten a leading zero ;)

Sadly, I fear that comments won't help in that situation. They could, except that the solution depends critically on the developer realizing they're writing garbled code during the time they're writing it. I don't know about anyone else, but my code's never garbled when I write it. It only becomes garbled by magic, and only when I don't look at it for a few weeks. Or, strangely enough, the moment someone else looks at it.

Still haven't figured out a reliable enough garble detection mechanism that my employer's willing to pay for.

Reply on news.ycombinator.com