PassiveSupport.List.cons
You're seeing just the function
cons, go back to PassiveSupport.List module for more information.
Link to this function
cons(list, item)
Specs
Returns a new list of [item | list]
An antonym to hd.
Examples
iex> cons([2,3], 1)
[1,2,3]
iex> [2,3] |> cons(1) |> cons(0)
[0,1,2,3]