Elixir deciding which control flow to use

control_flow.ex

# boolean values, use if
if expression, do: this(), else: that()

# non-boolean multi-value single expressions, use case
case expression do
  value1 -> one()
  value2 -> two()
  value3 -> three()
  _      -> anything_else()
end

# mutiple expressions, use cond
cond do
  expression_one() -> one()
  value1 == "this" -> "yes"
  expression_two() -> two()
end

# complex, nested conditions with type and/or value checks, use function pattern matching:
result = can_rent?(value)
def can_rent?(%App.User{age: age}) when age >= 30, do: true
def can_rent?(%App.Company{email: email, approved: true}) when is_binary(email), do: true
def can_rent?(%App.Employee{level: "senior"}), do: true
def can_rent?(_), do: false