Fix #45: cursor after Discard node should evaluate child

CHANGELOG.md

@@ -0,0 +1,5 @@
+# Changelog
+
+## Unreleased
+
+- Fix [#45](https://github.com/nextjournal/clojure-mode/issues/45): cursor after Discard node should evaluate child

public/squint/js/demo.mjs

@@ -2,6 +2,7 @@ import { default_extensions, complete_keymap } from '@nextjournal/clojure-mode';
 import { extension as eval_ext, cursor_node_string, top_level_string } from '@nextjournal/clojure-mode/extensions/eval-region';
 import { EditorView, drawSelection, keymap } from  '@codemirror/view';
 import { EditorState } from  '@codemirror/state';
+import { history, historyKeymap } from '@codemirror/commands';
 import { syntaxHighlighting, defaultHighlightStyle, foldGutter } from '@codemirror/language';
 import { compileStringEx } from 'squint-cljs';
 
@@ -89,10 +90,11 @@ let squintExtension = ( opts ) => {
                     }])}
 
 
-let extensions = [ theme, foldGutter(),
+let extensions = [ history(), theme, foldGutter(),
                    syntaxHighlighting(defaultHighlightStyle),
                    drawSelection(),
                    keymap.of(complete_keymap),
+                   keymap.of(historyKeymap),
                    ...default_extensions,
                    eval_ext({modifier: "Meta"}),
                    squintExtension({modifier: "Meta"})
@@ -120,6 +122,8 @@ let doc = `(comment
   (+ 1 2 3))
 `  ;
 
+// doc = `(do #_#_1 (+ 1 2 3) )`
+
 evalCode(doc);
 
 let state = EditorState.create( {doc: doc,
@@ -129,6 +133,7 @@ let editorElt = document.querySelector('#editor');
 let editor = new EditorView({state: state,
                              parent: editorElt,
                              extensions: extensions })
+globalThis.editor = editor;
 
 let keys = {"ArrowUp": "↑",
             "ArrowDown": "↓",

squint-demo/index.mjs

@@ -4,6 +4,7 @@ import { EditorView, drawSelection, keymap } from  '@codemirror/view';
 import { EditorState } from  '@codemirror/state';
 import { syntaxHighlighting, defaultHighlightStyle, foldGutter } from '@codemirror/language';
 import { javascript } from '@codemirror/lang-javascript';
+import { history, historyKeymap } from '@codemirror/commands';
 
 let theme = EditorView.theme({
   ".cm-content": {whitespace: "pre-wrap",
@@ -25,12 +26,13 @@ let theme = EditorView.theme({
   "&.cm-focused .cm-cursor": {visibility: "visible"}
 });
 
-let extensions = [
+let extensions = [ history(),
                    theme,
                    foldGutter(),
                    syntaxHighlighting(defaultHighlightStyle),
                    drawSelection(),
                    keymap.of(complete_keymap),
+                   keymap.of(historyKeymap),
                    ...default_extensions
                  ];
 

src-shared/nextjournal/clojure_mode/extensions/eval_region.cljc

@@ -12,12 +12,15 @@
 (defn uppermost-edge-here
   "Returns node or its highest ancestor that starts or ends at the cursor position."
   [pos node]
-  (or (->> (iterate n/up node)
-           (take-while (every-pred (complement n/top?)
-                                   #(or (= pos (n/end %) (n/end node))
-                                        (= pos (n/start %) (n/start node)))))
-           (last))
-      node))
+  (let [node (or (->> (iterate n/up node)
+                      (take-while (every-pred (complement n/top?)
+                                              #(or (= pos (n/end %) (n/end node))
+                                                   (= pos (n/start %) (n/start node)))))
+                      (last))
+                 node)]
+    (if (= "Discard" (n/name node))
+      (last (n/children node))
+      node)))
 
 (defn main-selection [state]
   (->
@@ -32,9 +35,10 @@
                         (<= (n/start %) from)
                         (<= (n/end %) from))
                 (cond-> %
-                  (or (n/top? %)
-                      (and (not (n/terminal-type? (n/type %)))
-                           (< (n/start %) from (n/end %))))
+                  (or
+                   (n/top? %)
+                   (and (not (n/terminal-type? (n/type %)))
+                        (< (n/start %) from (n/end %))))
                   (-> (n/children from -1) first))))
             (uppermost-edge-here from)
             (n/balanced-range state))))

test/nextjournal/clojure_mode_tests.cljc

@@ -331,7 +331,9 @@
         (= (f (test-utils/make-state extensions input)) expected)
       "(+ |1 2 3)" eval-region/cursor-node-string "1"
       "(+ |(+ 1 2) 2 3)" eval-region/cursor-node-string "(+ 1 2)"
-      "(+ (+ 1 2)| 2 3)" eval-region/cursor-node-string "(+ 1 2)")
+      "(+ (+ 1 2)| 2 3)" eval-region/cursor-node-string "(+ 1 2)"
+      "(+ #_(+ 1 2)| 2 3)" eval-region/cursor-node-string "(+ 1 2)"
+      "(+ #_#_1 (+ 1 2)| 2 3)" eval-region/cursor-node-string "(+ 1 2)")
     (let [state (test-utils/make-state extensions ";; dude\n|{:a 1}")]
       (is (= "{:a 1}" (->> (eval-region/top-level-node state)
                            (util/range-str state)))))))