defprotocol Quark.Sequence do
@moduledoc "A protocol for stepping through ordered enumerables"
@doc ~S"""
The beginning of the sequence.
For instance, integers are generally thought of as centering around 0.
## Examples
origin(9)
#=> 0
"""
@spec origin(any) :: any
def origin(specimen)
@doc ~S"""
The `succ`essor in sequence.
For integers, this is the number above.
## Examples
iex> succ(1)
#=> 2
iex> 10 |> origin() |> succ() |> succ()
#=> 2
"""
@spec succ(any) :: any
def succ(element)
@doc ~S"""
The `pred`essor in the sequence.
For integers, this is the number below.
## Examples
pred(10)
#=> 9
42 |> origin() |> pred() |> pred()
#=> -2
"""
@spec pred(any) :: any
def pred(element)
end
defimpl Quark.Sequence, for: Integer do
@doc ~S"""
## Examples
iex> origin(9)
0
"""
def origin(_num), do: 0
@doc ~S"""
## Examples
iex> succ(1)
2
iex> 10 |> origin() |> succ() |> succ()
2
"""
def succ(num), do: num + 1
@doc ~S"""
## Examples
iex> pred(10)
9
iex> 42 |> origin() |> pred() |> pred()
-2
"""
def pred(num), do: num - 1
end