Default completion doesn't work with pipe

[jcubic]

Issue summary

When using pipe extension completion: true doesn't work

Expected behavior

It should create completion when using object as interpreter

Steps to reproduce

1. Open Demo https://codepen.io/jcubic/pen/LYwNjrQ
2. press <TAB>

Browser and OS

N/A

Additional notes

The problem is that completion throws an error when used with a function interpreter. Maybe it should give a warning that you can't create a completion, or completion should be ignored.

https://codepen.io/jcubic/pen/vYoGJVV

[jcubic]

It seems that the code is correct, only the error message should be improved:

Instead of:

Invalid completion

The error should say something like:

Invalid completion: "automatic completion can't be used with a function interpreter"

Pipe creates an interpreter before it's passed to the library, so it is the same as creating a function as first argument.

But the pipe should create its own completion when object is used.

[jcubic]

It may be required to expose: make_interpreter function as __make_interpreter__ for the use in the pipe extension. This function will call callback with interpreter function and completion.