Ah, the three dots indicate where the object is put. Now I understand.

That’s right! The documentation do with a rewrite… (have now edited the description to mention that)

It is quite nice and readable However, it is also not so hard to replace with Kernel.then/2

could become

iex> 4 |> then(&div(2, &1))
0

4 |> then(&div(2, min(&1, 1)))
2

I see that the main difference between this and Magritte is that it do not have my limitations. Actually I have intentionally added these limitations to avoid things like:

foo
|> bar(fn a ->
  a
  |> baz(2137, ...) # what value should be inserted there?
end)

Also, when you want to use ... twice within single pipe there is question whether there should be 2 separate parent pipes or single one. Aka whether this code:

:rand.uniform()
|> Kernel.==(..., ...)

Should always return true?

I probably should have describe reasoning better in Magritte documentation.

I’ve added some more docs and examples: Arrows — arrows v0.2.1

Regarding ~> I tend to use it mostly for short pipes where with may feel verbose, but for longer ones I prefer to be more explicit. In part because of this gotcha:

      # Note that the following would pass :error to `String.pad_leading` breaking our pipe: 
      # :error ~> Integer.to_string() |> String.pad_leading(2, "0")
      :error

      # Instead we want to do:
      iex> :error ~> Integer.to_string() ~> String.pad_leading(2, "0")
      :error