One-liners and defp in Elixir

Two function shapes: the one-line do: body and the private helper only its module can call.

defmodule Tides do
  # A one-line body rides on the def itself with do:
  def high?(feet), do: feet >= 9.5

  def report(feet) do
    IO.puts("#{feet} ft -- #{advice(feet)}")
  end

  # defp makes a helper invisible outside the module
  defp advice(feet) do
    if high?(feet), do: "stay off the causeway", else: "safe to cross"
  end
end

Tides.report(11.2)
Tides.report(4.0)

How it works

def high?(feet), do: feet >= 9.5 puts a one-expression body on the def line itself.
report interpolates the reading and hands the judgment call to advice.
defp advice is private: inside the module an ordinary function, outside it does not exist.

Keywords and builtins used here

IO
Tides
def
defmodule
defp
do
end
if

The run, in numbers

Lines: 16
Characters to type: 354
Tokens: 77
Three-star pace: 80 tpm

At the three-star pace of 80 tokens a minute, this run takes about 58 seconds.

Type this snippet

Step 2 of 3 in Modules & functions, step 2 of 27 in Language basics.

← Previous Next →