Programming Languages Have Social Mores Not Idioms

Before I learned Ruby, I knew C, Obj-C, C++, Java...all languages that have and use "for" extensively. Coming to Ruby and learning "each" was an eye opening experience for me. Suddenly, the whole notion of iterators become clear to me. (While I had used them in the past, I had only marginally understood them.) After using "each" for a while, I came to realize that I was programming in a functional style without even knowing it.

Earlier today I read through Rich Hickey's posts explaining reducers and actually used them to get crazy performance gains from some Clojure code I was writing...but I highly doubt I would've gotten there without Ruby's "each".

I've seen Zed argue on this point before, and I've always been dubious of his "concern". The one point he makes here, though, that makes me side with him is that "for" is easier to teach than "each". Yes. A hundred times: yes!

The point I will disagree with him on is that "for" and "each" are interchangeable. Semantically, yes. Performance-wise, probably. But stylistically, "each" is a gateway drug to functional programming, and that should not be taken for granted.

(Edit: Where this all breaks down, and where I think Zed is experiencing frustration, is that while some people might have had a good reason for using "each", over time it became a social more. Now people teach and even enforce the use of "each" without being able to explain why. That doesn't mean one should avoid teaching "use each, not for", but it does mean that one should go and find out why.)

Start with "for". Teach "each".

...then go learn Clojure because hot DAMN reducers are going to revolutionize the way we program (but that's another topic for another day).

Looking at your own linked definition I think you're wrong:

1 : of, relating to, or conforming to idiom

2 : peculiar to a particular group, individual, or style

That again says it's a local construct that isn't a clear universal usage. If you want to be clear in your writing then you avoid idiomatic speech.

This also doesn't disprove my point that the way these supposed "idioms" cause derision and overreaction says they are now social mores.

Well remember, I'm not against .each at all. I'm against it as a first looping construct for beginners. I even start people off in my book by sneaking in functional programming, again because it's easier to teach. They even write a game that is basically one giant sequence of mostly tail calls without knowing it.

Outside of the last point about the each method not being a good first exposure to looping, the article was mainly just debating the definition of idiom. That's irrelevant because definitions of English words are overloaded in different fields such as CS all the time.

Nevertheless, this use of idiom does seem consistent with its normal usage. In the context of natural languages, an idiom can mean a phrase of arbitrary origin that has come to have a specific meaning in specific dialects (this is referred to as an idiomatic expression), but the adjective idiomatic can also be used in the sense of "what sounds most conventional to a native speaker" [1]. Likewise, in programming languages, I think of something as being "idiomatic" if it follows either formal conventions [2] or is a commonly used construct.

As for the author's negative opinion of having idioms in a language, I'd imagine most programmers advocate conventions in order to keep code somewhat consistent across programmers. If you didn't have them at all and if every programmer used different constructs to do the same thing, programmers wouldn't be able to use pattern recognition to read others' code and all code written by multiple people would be even harder to decipher than poorly written Perl since there would be infinitely many ways to do it. TWBIMWTDI? :)

[1] I don't want to say what sounds "right" (hence my use of "conventional") since that would necessitate a lengthy discussion about grammatical prescriptivism, but just note that colloquial expressions like "the people who I gave the ball to" can be considered just as idiomatic (under this definition) as formal expressions like "the persons to whom I gave the ball", even if prescriptivists would define only the latter as "correct".

[2] Unlike natural languages whose syntax is naturally occurring, prescriptivism in programming languages makes sense since they're invented by humans to make writers, readers, and/or revisers of code more productive.