View Source Bunch.Typespec (Bunch v1.6.1)

A bunch of typespec-related helpers.

Summary

Functions

@expr

This macro is deprecated. Use Bunch.Typespec.enum_to_alternative/1 instead.

enum_to_alternative(list)

Converts an enumerable of terms to AST of alternative type of these terms.

Functions

Link to this macro

@expr

View Source (macro)

This macro is deprecated. Use Bunch.Typespec.enum_to_alternative/1 instead.

Allows to define a type in form of t :: x | y | z | ... and a module parameter in form of @t [x, y, z, ...] at once.

Example 

defmodule Abc do
  use Bunch.Typespec
  @list_type t :: [:a, :b, :c]
  @spec get_at(0..2) :: t
  def get_at(x), do: @t |> Enum.at(x)
end

Abc.get_at(1) # -> :b
Link to this function

enum_to_alternative(list)

View Source 
@spec enum_to_alternative(Enumerable.t()) :: Macro.t()

Converts an enumerable of terms to AST of alternative type of these terms.

Useful for defining a type out of a list of constants.

Examples 

iex> defmodule Example do
...>   @values [1, :a, {true, 3 * 4}]
...>   @type value :: unquote(Bunch.Typespec.enum_to_alternative(@values))
...>   @spec get_value(0..2) :: value
...>   def get_value(i), do: Enum.at(@values, i)
...> end
iex> Example.get_value(1)
:a

iex> Bunch.Typespec.enum_to_alternative([1, :a, {true, 3 * 4}])
quote do
  1 | :a | {true, 12}
end