Takes in a tuple and function from plain value to {:ok, any} | {:error, any}. Applies the function to the value within the ok tuple or propogates the error.

Examples:

iex> bind({:ok, 1}, fn x -> if x == 1, do: {:ok, 2}, else: {:error, "not_one"} end)
{:ok, 2}

iex> bind({:ok, 4}, fn x -> if x == 1, do: {:ok, 2}, else: {:error, "not_one"} end)
{:error, "not_one"}

iex> bind({:error, 4}, fn x -> if x == 1, do: {:ok, 2}, else: {:error, "not_one"} end)
{:error, 4}

Wraps value in an error tuple Will be inlined at compile time.

Typespec:

error(any) :: t()

Extracts the value or reason from the tuple. Caution: If given an error tuple it raise an exception!

Takes in a tuple and a function from plain value to plain value. Applies the function to the value within the ok tuple or propogates error.

Examples:

iex> {:ok, 6}
...> |> fmap(fn x -> x+2 end)
{:ok, 8}

iex> {:error, 6}
...> |> fmap(fn x -> x+2 end)
{:error, 6}

Ignores the value in an ok tuple and just returns :ok. Still shortcircuits on error.

Examples:

iex> {:ok, 2}
...> |> ignore
:ok

iex> :ok
...> |> ignore
:ok

iex> {:error, :not_found}
...> |> ignore
{:error, :not_found}

Wraps value in an ok tuple. Will be inlined at compile time.

Typespec:

ok(a) :: s(a) when a: var

This is infix bind/2 Has same syntax restrictions as pipe. Defined as a macro for syntatic purposes.

Examples:

def sgn(x) do
  if x > 0 do
    {:ok, "pos"}
  else
    {:error, "neg"}
  end
end

def two_args(x, y), do: {:ok, x - y}

{:ok, 1}
~> sgn
= {:ok, "pos"}

{:ok, -3}
~> sgn
= {:error, "neg"}

{:error, 2}
~> sgn
= {:error, 2}

{:ok, 3}
~> two_args(2)
= {:ok, 1}

Typespec:

t(a) ~> (a -> t(b)) :: t(b) when a: var, b: var