Idioms are a big deal in any language. They represent deep knowledge beyond syntax and grammar, a feel for getting the most out of the language.

For example, when non-English speakers become fluent in English, they usually speak in a “textbook” way. One might see a celebrity receive a light punishment for a major crime and say, “That individual most assuredly did not receive a punishment commensurate with the gravity of the crime.” Meanwhile, a native English speaker might say instead, “Dude! Really? That’s a slap on the wrist!” What the non-native English speaker says is formal and correct, but it doesn’t reflect a deep understanding of the language or comfort with its idiosyncrasies.

Idioms are just as important in programming languages.

When I first started writing Ruby code, it was after many years of writing Java code. It showed. It looked like Ruby code written by a Java guy. It still worked, but it didn’t give me a feel for how Ruby works. Worse yet, I wasn’t taking advantage of the cool features Ruby has that Java doesn’t.

Here is a Ruby function written in a non-idiomatic way.

Except for the def, which is more reminiscent of Groovy, this function looks very Java. It takes a string parameter (or so we assume since Ruby is dynamic) and checks if it contains a space. If it does, return the string in lowercase with the space removed. If not, return the string in uppercase. Contrived but straightforward. And very Java-looking.

Compare that to the idiomatic Ruby equivalent

Notice a few differences:

  • The unless keyword in Ruby to indicate “if not”
  • The condition on the same line (which you can do with if or unless)
  • No parentheses necessary around the parameter to include?
  • A second return statement unnecessary since the last line is returned

As you can see, idiomatic Ruby is more concise and leverages core language features that are pretty cool and absent from Java.

Now check out a very Java-looking loop

This loops 100 times and prints out the current number. It looks very familiar to a Java developer.

Compare that to the idiomatic Ruby equivalent

Notice the differences:

  • Underscore syntax for the function name rather than the lower camel case of Java
  • The times method called on 100 because it is an object—not a primitive like in Java
  • The each method called on the times enumerator

In this case, idiomatic Ruby is not more concise. But as Russ Olsen points out in Eloquent Ruby, the foremost authority on idiomatic Ruby, the Java-like loop syntax is actually syntactic sugar for the idiomatic loop syntax. The Ruby community prefers the idiomatic syntax. So should you.

These are simple examples. I didn’t even get into the idiomatic Ruby awesomeness at your disposal with collections thanks to its support for functional programming constructs (even though Ruby is not a functional language).

I’m not saying Ruby idioms are superior to Java idioms. You simply should write idiomatic code for whichever language you’re using. A Ruby developer moving to Java would have to learn to use lower camel case, if blocks, and so on.

Idiomatic code is critical for several reasons. It will often be more concise than the alternative. You will take advantage of the powerful features that have presumably made the language popular. You will also become a student of languages and understand the pros and cons of static vs. dynamic, imperative vs. functional, etc., which will make it easier to learn new languages and stay ahead in technology. Finally, your colleagues at work will be more likely to understand and maintain your code. That needs to be a priority for you if you want to be a truly professional developer and team player.

Keep idioms in mind as you become an expert polyglot developer. You will write better code and prove very marketable.