zipper: issue with latest test case from sync

[SleeplessByte]

[Original Issue:]

The following test is missing:

# different paths to same zipper
"47aa85a0-5240-48a4-9f42-e2ac636710ea" = true

[sachinmk27]

I'd like to work on this

[joshgoebel]

@SleeplessByte I don't understand this test at all... It seems wholly at odds with the problem specificiation:

• prev (move the focus to the previous child of the same parent, returns a new zipper)
• next (move the focus to the next child of the same parent, returns a new zipper)
• up (move the focus to the parent, returns a new zipper)
• set_value (set the value of the focus node, returns a new zipper)

All mutation/navigation returns a new zipper, this directly contradicts the most recent test of "same zipper".

Should I open a new issue?

[joshgoebel]

To me I see 3 levels of abstraction here...

1. the underlying node data in memory
2. the JavaScript reference to a node (variable, object key, etc)
3. the Zipper instance (which holds unto a node reference)

I might have two zippers a and b that hold the same reference (2) to the same data(1) - because they are the same path (even if arrived at my different routes), but they are (in my implementation) different pointer instances (3)... I'm confused as to why this should be a requirement or even exactly what it means for it to be a requirement.

The directions say nothing about this requirement.

Questions:

• It seems that what matters here should be 1/2 (pointer equality) not 3 (whether we have 1 or 2 discrete pointers), no?
• And of course this stops being true if one calls a set anywhere along the route, correct?
• How does this test even pass given the code for right - it literally calls new Zipper() always...

[joshgoebel]

This also seems a direct contradiction of the immediate prior test:

  test('up returns a new Zipper', () => {
    const up = zipper.right().up();
    expect(zipper).not.toBe(up);
  });

These are the same path (root), so why are they not the "same" zipper?