Étude 3-1: Pattern Matching in Elixir and Erlang

gistfile1.erl

### Elixir    

defmodule Geom do
  def area(:rectangle, length, width) do
    length * width
  end

  def area(:triangle, base, height) do
    base * height / 2
  end

  def area(:ellipse, a, b) do
    a * b * :math.pi 
  end
  
end


### Erlang

-module(geom).
-export([area/3]).

area(rectangle, Length, Width) -> Length * Width;
area(ellipse, A, B)            -> math:pi() * A * B;
area(triangle, Base, Height)   -> Base * Height / 2.
  

You can rewrite the code like this:

### Elixir    
defmodule Geom do
  def area(:rectangle, length, width) do: length * width
  def area(:triangle, base, height) do: base * height / 2
  def area(:ellipse, a, b) do: a * b * :math.pi 
end

It seems that the final end is mandatory, thou :(

defmodule Geom do
  def area(:rectangle, length, width) do: length * width end
  def area(:triangle, base, height) do: base * height / 2 end
  def area(:ellipse, a, b) do: a * b * :math.pi end
end

It's not necessary, but I missed a comma:

defmodule Geom do
  def area(:rectangle, length, width), do: length * width 
  def area(:triangle, base, height), do: base * height / 2
  def area(:ellipse, a, b), do: a * b * :math.pi
end