Find the Erlang version you’re running:

erlang:system_info(otp_release).

To clear a variable/binding, so it can be used again:

f(variable_to_clear).

Show all the running erlang processes:

erlang:processes().

Find more useful tips from Joe (such as how to ping a node with a dash in the name).

Helpful Erlang Tidbits

Here’s what we came up with:

Java: Protect the Developer From Themselves

Ruby: Be the Developer’s Language

Python: There is One True Way

PHP: eh

Do you agree? Disagree? What are the one sentence philosophies behind other languages that we didn’t touch on?

Language Design Philosophies

The story touches on languages and how gender in languages affects thinking.  It is highlighted that Spanish speakers and Germany speakers pick different adjectives to describe a bridge, based on the fact that in one language a bridge is male, in the other, female.

The story goes on to talk about how scientists set up an experiment to determine if it was language that the differences could be attributed to.  They determined it is language and that you can shift people’s thinking by teaching them a language that uses different gender constructs.

The story then goes on to talk about Shakespeare’s famous line: A rose by any other name would smell as sweet.

Here’s the actual, full quote:

What’s in a name? that which we call a rose
By any other name would smell as sweet
-Act II, Scene II. Romeo and Juliet

It’s a very interesting story and well worth the seven minutes it takes to listen to.

As an added bonus, Knowing and Doing just posted a post titled Language Driven Programming, which tackles many of the same themes and applies them to programming languages.

NPR on the Sapir-Whorf Hypothesis

In the third part of the series, Dispatch, Stuart writes about ways the Java.next languages dynamically choose behavior, one such way being with the switch statement.  Stuart provides examples in Ruby (technically he should have used JRuby), Groovy, Clojure, and Scala.  Stuart explores further than just the switch statement, but it was the switch statement example that caught my eye.

The example for each language is a simple piece of code that takes a grade (either numeric or letter) and returns the letter equivalent.  If passed a 95, the code returns A.  If passed 55, it returns F.  If passed B, it returns B.  If passed something that doesn’t equate to a valid grade, it throws an error.

I couldn’t resist coding it in Erlang.

Here is what I came up with:

-module(grades).
-export([grades/1]).

grades(N) ->
  case N of
    N when is_integer(N), N >= 90 -> "A";
    N when is_integer(N), N >= 80 -> "B";
    N when is_integer(N), N >= 70 -> "C";
    N when is_integer(N), N >= 60 -> "D";
    N when is_integer(N), N >= 0  -> "F";
    "A" -> "A";
    "a" -> "A";
    "B" -> "B";
    "b" -> "B";
    "C" -> "C";
    "c" -> "C";
    "D" -> "D";
    "d" -> "D";
    "F" -> "F";
    "f" -> "F";
    N when true -> throw("Not a valid grade")
 end.

Now for the embarrassing admission: this code took me way longer to complete than it should have.  I couldn’t remember the proper syntax for anything and I kept attempting to code Erlang like I was coding Python.  I’m sure it’s not done the Erlang way and that I’ve missed someway to make it more compact.  However, the code does work.

If you have a better solution, please submit it in the comments. If something can be improved, I always welcome knowing how.

Java.beyond

Unfortunately, PHP does not have one natively.  However, I just discovered that Facebook has opened sourced a REPL for PHP – so now you can test out your PHP code without needing to write and run a script.

Working in Python, I’ve found Python’s REPL highly convenient, so I’m going to start using Facebook’s PHP REPL for when I have to work in PHP.

Ironically, Facebook’s PHP REPL is implement in Python. I can commiserate: given the choice between Python and PHP, I’d go with Python.

PHP REPL