Pretty view mode

[r0man]

Hello,

this PR adds the pretty printer from https://github.com/eerohele/pp (as suggested by @alexander-yakushev) and some of its tests, and a configuration option to toggle the pretty printing with the "P" key binding in the CIDER inspector.

The top level keys are rendered in the "inspector mode" as I understood it from a conversation on Slack.

The changes needed for the middleware can be found here: clojure-emacs/cider-nrepl#932
The changes for CIDER are here: clojure-emacs/cider#3813

The data structure shown on the following pictures was this:

{{:a 0
  :bb "000"
  :ccc []
  :d [{:a 0 :bb "000" :ccc []}
      {:a -1 :bb "111" :ccc [1]}
      {:a -2 :bb "222" :ccc [2 1]}
      {:a -3 :bb "333" :ccc [3 2 1]}
      {:a -4 :bb "444" :ccc [4 3 2 1]}]}
 {:a -1
  :bb "111"
  :ccc [1]
  :d [{:a 0 :bb "000" :ccc []}
      {:a -1 :bb "111" :ccc [1]}
      {:a -2 :bb "222" :ccc [2 1]}
      {:a -3 :bb "333" :ccc [3 2 1]}
      {:a -4 :bb "444" :ccc [4 3 2 1]}]}}

Without pretty printing enabled (as before):

With pretty printing enabled (in normal mode):

With pretty printing enabled (in object mode):

Wdyt?

Open questions:

• Pretty printing applies only to collections as of now. Are there other objects except from collections that should be pretty printed differently?
• I removed many of the pp tests and now kept only some of them in the pp_test.clj file.
• I noticed the "Value" in :object mode did also got pretty printed with this change, but the indentation was off, so I adjusted this as well.
• Huge maps can look bad even in pretty mode. I tried it with one of our component system maps at work. I think the rendering could be improved if the content of a record (the {...} map after the record name) would be printed on a new line. Was the plan for the pretty printer to modify it for our needs?

TODOs:

• I added 2 tests to orchard.print-test. They are passing in the REPL but fail when I run them with lein test orchard.print-test in Leiningen. For some reason they are printed differently in Leiningen. Any idea why that is? The atom (atom 1) for example is printed as "#atom[1 0x4f9ea948]" in the REPL, but like this #object[clojure.lang.Atom 0x3a718b52 {:status :ready, :val 1}] from Leiningen. I already checked that the various *print-XXX* vars are bound to the same value. It seems they are. What else could affect the printing?

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[alexander-yakushev]

Thanks for putting in the work, @r0man! I left a few comments.

[alexander-yakushev]

Still not quite what I meant:) You can print the key with print-string first. That gives you a string that you can check if it's long or has newlines and you don't have to dig it out of :rendered list and parse it. And once you have a printed string, you can pass it to render-value via :display-value.

[alexander-yakushev]

Another thing: even though it is a config option now, I think it will still be beneficial to have a toggle-pretty-print function similar to toggle-view-mode, so that we can then also have a toggle op on cider-nrepl and thus on CIDER we can have a toggle command that doesn't need to know on Elisp side whether the pretty-printing is currently enabled.

[alexander-yakushev]

Whoops, sorry for confusing you! I forgot that toggle-view-mode is implemented completely on cider-nrepl side. Right, it is enough to have :pretty-print as a configuration option, and then implement toggle-pretty-print in cider-nrepl since it has complete access to inspector state anyway. Sorry again.

[r0man]

@alexander-yakushev No worries, I think what you describe in your last comment was my latest plan. Was your comment about adding the inspect-toggle-pretty-print NREPL op AND adding a toggle-pretty-print function to the orchard inspector, which the middleware would call? I thought about doing this, but have not worked on it yet. Given that we usually just delegate to the orchard inspector, why would you not do it in this case?

[alexander-yakushev]

I think it is perfect as it is. Let's merge!

adding a toggle-pretty-print function to the orchard inspector, which the middleware would call?

Yeah, I suggested this and then understood it is not necessary.