Elixir: Module: cond construct

‘cond’ construct converts numerical values to atoms

In the Elixir module above, the cond construct evaluates each expression for the first clause which evaluates to a truthy value, based on the velocity value’s range, then converts a numerical float value from the case construct to an atom which describes velocity range.

• 0 to :stable
• 1–5 to :slow
• 6–10 to :moving
• 11–20 to :fast
• 21+ to :speedy

In the cond construct, :stable, :slow, :moving, :fast and :speedy are atoms. In the case construct, are the atoms :earth, :moon and :mars.

To run the module, it first needs to be compiled (see interaction below). Then, if the Earth distance value is 20, then Drop.fall_velocity(:earth,20) could be entered at the Elixir interactive shell prompt (IEx):

iex(1)> c("drop.ex")                 
[Drop]
iex(2)> Drop.fall_velocity(:earth, 20)
:fast
iex(3)> Drop.fall_velocity(:earth, 21)
:speedy

Introducing Elixir