add extract-function

Author: Case Nelson

README.md

@@ -54,7 +54,7 @@ Using Vundle, add this to your vundle .config/nvim/init.vim section:
 - [ ] [describe-refactor](https://github.com/clojure-emacs/clj-refactor.el/blob/master/examples/describe-refactor.gif)
 - [ ] [destructure-keys](https://github.com/clojure-emacs/clj-refactor.el/blob/master/examples/destructure-keys.gif)
 - [x] `crel` [expand-let](https://github.com/clojure-emacs/clj-refactor.el/blob/master/examples/expand-let.gif) * Doesn't yet replace other usages of bindings
-- [ ] [extract-fn](https://github.com/clojure-emacs/clj-refactor.el/blob/master/examples/extract-fn.gif)
+- [x] `cref` [extract-fn](https://github.com/clojure-emacs/clj-refactor.el/blob/master/examples/extract-fn.gif)
 - [ ] [find-usages](https://github.com/clojure-emacs/clj-refactor.el/blob/master/examples/find-usages.gif)
 - [ ] [hotload-dependency](https://github.com/clojure-emacs/clj-refactor.el/blob/master/examples/hotload-dependency.gif)
 - [ ] [inline-symbol](https://github.com/clojure-emacs/clj-refactor.el/blob/master/examples/inline-symbol.gif)

plugin/refactor.vim

@@ -5,6 +5,7 @@ noremap crci :CCycleIf<CR>
 noremap crcp :CCyclePrivacy<CR>
 noremap crct :CCycleThread<CR>
 noremap crel :CExpandLet<CR>
+noremap cref :CExtractFunction 
 noremap crfe :CFunctionFromExample<CR>
 noremap cril :CIntroduceLet 
 noremap crml :CMoveToLet 

rplugin/node/clj-refactor.js

@@ -98,7 +98,10 @@
                repl/rename-dir)
      (.command js/plugin "CRenameSymbol"
                #js {:eval "[getcwd(), expand('%:p'), fireplace#ns(), expand('<cword>'), fireplace#info(expand('<cword>')), getpos('.')]" :nargs 1}
-               (partial repl/extract-definition repl/rename-symbol)))
+               (partial repl/extract-definition repl/rename-symbol))
+     (.command js/plugin "CExtractFunction"
+               #js {:eval "[expand('%:p'), getpos('.')]" :nargs 1}
+               (partial repl/find-used-locals run-transform transform/extract-function)))
 
    (catch js/Error e
      (jdbg "main exception" e))))

src/clj_refactor/main.cljs

@@ -120,6 +120,7 @@
 (defn rename-symbol
   [nvim sym-ns sym-name defs new-symbol]
   (go
+    ;; TODO look at clj-refactor.el for safer impl
     (let [wait-ch (chan)]
       (let [{:keys [line-beg col-beg file name]} (:definition defs)]
         (.command nvim (str "e " file " | "
@@ -135,3 +136,18 @@
                   (fn [err]
                     (close! wait-ch)))
         (<! wait-ch)))))
+
+(defn find-used-locals
+  [run-transform transform-fn nvim args [file [_ row col _]]]
+  (fireplace-message
+   nvim
+   {:op "find-used-locals"
+    :file file
+    :line row
+    :column col}
+   (fn [err results]
+     (js/debug "find-used-locals" err results)
+     (if-let [error (aget (first results) "error")]
+       (.command nvim (str "echo \"" error "\""))
+       (let [used-locals (seq (js->clj (aget (first results) "used-locals")))]
+        (run-transform transform-fn nvim (conj (js->clj args) used-locals) [0 row col 0]))))))

src/clj_refactor/repl.cljs

@@ -266,3 +266,18 @@
       (z/insert-left `(~'defn ~fn-name [~@args])) ; add declare
       (z/insert-left (n/newline-node "\n\n"))))) ; add new line after location
 
+(defn extract-function
+  [zloc [fn-name used-locals]]
+  (let [expr-loc (z/up (edit/find-op zloc))
+        expr (z/sexpr expr-loc)
+        fn-sym (symbol fn-name)
+        used-syms (map symbol used-locals)]
+    (-> expr-loc
+      (z/replace `(~fn-sym ~@used-syms))
+      (edit/exec-to z/up #(not (edit/top? %))) ; Go to top level form
+      (z/insert-left `(~'defn ~fn-sym [~@used-syms] ~expr))
+      (z/insert-left (n/newline-node "\n\n"))
+      (z/left)
+      (z/up))))
+
+

src/clj_refactor/transform.cljs

@@ -97,3 +97,12 @@
 
        '(do (defn b [arg1 z]) (defn a [z] (b (x y) z)))
        (apply-zip-root '(defn a [z] (b (x y) z)) 'b t/function-from-example)))
+
+(deftest testing-extract-function
+  (are [i j] (= i j)
+       '(do (defn my-fn [c] (a (b c)))
+            (defn old-fn [] (let [c 1] (my-fn c))))
+        (apply-zip-root '(defn old-fn [] (let [c 1] (a (b c))))
+                        'a
+                        #(t/extract-function % ["my-fn" ["c"]]))))
+