Add pagination of long collections to inspector

[alexander-yakushev]

Frontend part of the pagination feature.

Keys are arbitrary, suggestions are welcome.

• . for next page
• , for previous page
• z to set a new page size inside the inspector

Missing features:

• specifying a default page size. Right now it is hardcoded to 32.

Sister pull request is clojure-emacs/cider-nrepl#238.

[Malabarba]

(interactive "nPage size: ") is probably enough (and might be slightly more appropriate).

[Malabarba]

Looks good to me. (The clj side too).

For the keys, np are good candidates, and I think jk or hl will make sense to a lot of (vim) people. If we want to imitate Emacs help buffers, C-c C-b and C-c C-f are the keys used.

That said, having actual previous/next page buttons would probably be the most help to most people.

[Malabarba]

I just noticed this, but docstrings would be nice too. Specially since they're user level commands.

[alexander-yakushev]

Done. I'll wait for @bbatsov to say his word about keybindings and then change them too.

[bbatsov]

The new functionality should also be mentioned in the changelog.

Btw, how did you derive the 32 default?

[alexander-yakushev]

Btw, how did you derive the 32 default?

By raising 2 to power of 5 ;).

[bbatsov]

specifying a default page size. Right now it is hardcoded to 32.

So the only question now is are we doing this as part of the current PR. I can imagine it'd be nice for this to be some defcustom, but there should also be some command to change the value on the fly.

[alexander-yakushev]

There is a way to change it on the fly with z. If we want to hold the default in a variable, we have to pass it at the beginning of the inspection, I suppose.

Please also suggest a replacement for z. I don't like it personally, but it was the first thing that came into my mind thinking of siZe.

[bbatsov]

There is a way to change it on the fly with z. If we want to hold the default in a variable, we have to pass it at the beginning of the inspection, I suppose.

Yeah. The debugger does this for its object print length settings. That should be easy to do for the inspector as well.

Please also suggest a replacement for z. I don't like it personally, but it was the first thing that came into my mind thinking of siZe.

No brilliant ideas here. I'd just suggest something that's easier to press (doesn't require the use of the little finger).

[alexander-yakushev]

s might work, and keeps it somewhat mnemonic (Size), and the binding is uncommon enough.

Done with the default page size.

[bbatsov]

I'm fine with s.

[bbatsov]

Sending nil to nREPL will byte you, as it gets encoded as an empty vector. :-) It's best to simply not send it at all, when nil. Here's an example.

[alexander-yakushev]

So do I check for nil first, and if it is nil, I don't send that value? Sounds messy. Maybe just (or it with a hardcoded default?

[bbatsov]

That's what we do everywhere. It's not ideal, but you can't simply encode EL nil as a Clojure nil, as it's also an empty list in Emacs Lisp, and you can never know what exactly was it used to represent.

[alexander-yakushev]

Added a call to or. The case is already very marginal, someone will have to deliberately change the default page size and set it to nil. I'd say let them burn then, but OK.

[bbatsov]

I'd say the Emacs part looks solid. Just get the Clojure tests passing and I'll have this merged.

[alexander-yakushev]

They are passing. Eastwood and cljfmt cannot into modern threading macros.

[bbatsov]

Victory!

[alexander-yakushev]

🎉