elixir-lang/elixir — pull request #1060 by mururu (2013-05-14 08:52:12+00:00)
Title: Add a prefix in front of return value in iex

I want a prefix like `=>` in Ruby in front of a return value in iex because this makes easy to distinguish the return value from io.

```
iex(1)> IO.puts "a"
a
:ok
```

```
iex(1)> IO.puts "a"
a
=> :ok
```