Hacker News Reader

Comment by pjungwir | Hacker News Reader

I suppose this is a tangent, but a lot of this refactoring strikes me as obfuscation. Defining methods named `multiple_of_3` and `multiple_of_5` just to encapsulate a mod? I'd rather just read `x % 3 == 0` and `x % 5 == 0` than look up a method definition.

And then he makes it worse by throwing those out, defining `multiple_of`, and using method_missing to make `multiple_of_{3,5}` still work. A big part of reading unfamiliar code is looking up the implementation of things, and this is just making it more laborious and confusing.

View on HN

Completely agreed. Just defining a "multiple_of" method which takes n as a parameter would have better than the method_missing hack.

"I'd rather just read x % 3..."

Lots of people don't know of % works. Just as a lot of C / Java / C# programmers do not know the difference between "if a() & b()" and "if a() && b()".

Note that I'm not saying it's great to use "if a() & b()". All I'm saying is most people do not know the difference.

Try it if you interview people. It's fascinating. And, no, I'm not disqualifying people if they don't know the difference ; )

Lots of people don't know of % works. Just as a lot of C / Java / C# programmers do not know the difference between "if a() & b()" and "if a() && b()"

Funny you say that. And incredibly sad too.

I have participated in interviewing many junior/mid/senior developers and you are correct that they trip up on the % operator. I've also experienced them tripping up on the word "modulo" and instead trying to calculate the remainder of a division operation by hand.

While not trying to be elitist, I'm not sure what it says about our industry when a fundamental concept such as modulus is not understood by programmers.

That reminds me of a co-worker who was weirded out by my using "modulo" to mean "except for" or "ignoring" (which is, to my understanding, perfectly ordinary English).

They did, thankfully, fully understand it in a mathematical context - to my knowledge I've never worked with someone who didn't, although this and nearby comments are leaving me wondering...

This is the first time I've heard it outside of a mathematical context. I'm an undergrad student.

Not saying it's incredibly common, by any stretch.

FWIW, wiktionary.com and thefreedictionary.com have the usage, Merriam Webster does not. Don't know about OED (don't have access).

I've occasionally tried to work out a sensible rationale for the non-mathematical meaning based on the mathematical one. Perhaps this is etymologically unsound, but hey, words are fun. But how do you get from "remainder when divided by" to "except"? I guess `x % y` gives you "the leftovers," which is close enough to "except."

Oh, that's straightforward. In a truly mathematical context, modulo isn't really an operator per se.

You can say,

10 = 7 modulo 3

Which is kinda, "10 = 7, except someone may have added some number of threes to each" - so, "10 = 7, but for the threes"

> Lots of people don't know of % works.

God, really? But they know what a multiple is?

I doubt I'd hire a C programmer who didn't recognize a bit operator. Yikes! Even for Java/C#, it seems disconcerting, doesn't it?

Reply on news.ycombinator.com