Add paredit setup for edn-mode

[grzm]

Like clojure-mode, edn-mode needs to coax paredit to auto-pair curly braces.

I've replicated the minimum set of features from the existing clojure-paredit-setup to edn-paredit-setup to allow auto-pair functionality for curly braces ({)

I tried to a test to confirm the behavior, but my emacs/buttercup testing skills aren't currently up to the task. Here's what I (naïvely) tried (added to edn-mode-indentation-test.el for experimentation).

(require 'paredit)

(describe "edn-mode paredit support"
          (describe "auto-pairs curly braces"
                    (it "should add a closing brace with an opening brace is inserted"
                        (with-edn-buffer ""
                                         (paredit-mode)
                                         (insert "{")
                                         (expect (buffer-string) :to-equal "{}")))))

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Thanks!

[bbatsov]

Thanks for the PR! The problem diagnosis is correct — edn-mode-map has prog-mode-map as parent, not clojure-mode-map, so the paredit {/} bindings from clojure-paredit-setup don't reach EDN buffers.

However, I think we can fix this without duplicating the setup function. The root cause is that clojure-paredit-setup defaults to clojure-mode-map when no keymap is passed. If we change it to default to (current-local-map) instead, the existing paredit-mode-hook (which edn-mode already inherits from clojure-mode) will just work for all derived modes automatically.

Something like:

(let ((keymap (or keymap (current-local-map))))

That single-line change should fix EDN mode (and any future derived modes) without needing edn-paredit-setup at all.