Croma

Elixir macro utilities

Croma.Defun

Type specification oriented function definition

• Example 1

    import Croma.Defun
    defun f(a: integer, b: String.t) :: String.t do
      "#{a} #{b}"
    end

is expanded to

```ex
@spec f(integer, String.t) :: String.t
def f(a, b) do
  "#{a} #{b}"
end
```

• Example 2

    import Croma.Defun
    defun dumbmap(as: [a], f: (a -> b)) :: [b] when a: term, b: `term do
      ([]     , _) -> []
      ([h | t], f) -> [f.(h) | dumbmap(t, f)]
    end

is expanded to

```ex
@spec dumbmap([a], (a -> b)) :: [b] when a: term, b: term
def dumbmap(as, f)
def dumbmap([], _) do
  []
end
def dumbmap([h | t], f) do
  [f.(h) | dumbmap(t, f)]
end
```

• Known limitations:
  • Pattern matching against function parameters should use (param1, param2) when guards -> block style.
  • Overloaded typespecs are not supported.