From 7af1f7cad2d237b9aad972bd498b4ef8c3b0781c Mon Sep 17 00:00:00 2001
From: Tomas Brejla <brdloush@gmail.com>
Date: Fri, 9 Jul 2021 22:16:52 +0200
Subject: [PATCH] optimize rangeForDefun slowing repl printout #942

---
 src/cursor-doc/token-cursor.ts | 55 +++++++++++++++++++++++-----------
 1 file changed, 38 insertions(+), 17 deletions(-)

diff --git a/src/cursor-doc/token-cursor.ts b/src/cursor-doc/token-cursor.ts
index d9d4d7f2f..833d289f6 100644
--- a/src/cursor-doc/token-cursor.ts
+++ b/src/cursor-doc/token-cursor.ts
@@ -612,25 +612,46 @@ export class LispTokenCursor extends TokenCursor {
      * @param commentIsTopLevel? Controls
      */
     rangeForDefun(offset: number, depth = 0, commentCreatesTopLevel = true): [number, number] {
-        const cursor = this.clone();
-        while (cursor.forwardSexp()) {
-            if (cursor.offsetEnd >= offset) {
-                if (depth < 1 && cursor.getPrevToken().raw === ')') {
-                    const commentCursor = cursor.clone();
-                    commentCursor.previous();
-                    if (commentCursor.getFunctionName() === 'comment' && commentCreatesTopLevel) {
-                        commentCursor.backwardList();
-                        commentCursor.forwardWhitespace();
-                        commentCursor.forwardSexp();
-                        return commentCursor.rangeForDefun(offset, depth + 1);
-                    }
+        const cursor = this.doc.getTokenCursor(offset);
+        if (cursor.getPrevToken().raw == ')') {
+            cursor.backwardSexp();
+        }
+        if (cursor.getToken().type === 'eol' || cursor.getToken().type === 'ws') {
+            cursor.forwardWhitespace();
+        }
+        if (cursor.getToken().raw == '(') {
+            cursor.next();
+        }
+        if (cursor.getToken().raw === 'comment' && commentCreatesTopLevel) {
+             cursor.next();
+             cursor.forwardWhitespace();
+        }
+        if (cursor.getToken().raw == '(') {
+            cursor.next();
+        }
+        do {
+            let rowColBefore = cursor.rowCol;
+            const peekForwardUpPrevCursor = cursor.clone();
+            peekForwardUpPrevCursor.forwardList();
+            peekForwardUpPrevCursor.upList();
+            peekForwardUpPrevCursor.previous();
+            if (peekForwardUpPrevCursor.getFunctionName() === 'comment' && commentCreatesTopLevel) {
+                break;
+            }
+            cursor.forwardList();
+            if (!cursor.upList()) {            
+                if (cursor.getPrevToken().type === 'eol' && cursor.getToken().type === 'eol') {
+                    return [offset, offset]
+                } else {
+                    return cursor.rangeForCurrentForm(0);
                 }
-                const end = cursor.offsetStart;
-                cursor.backwardSexp();
-                return [cursor.offsetStart, end];
             }
-        }
-        return [offset, offset]
+            let rowColAfter = cursor.rowCol;
+            if (rowColAfter[0] == rowColBefore[0] && rowColAfter[1] == rowColBefore[1]) {
+                break;
+            }
+        } while (cursor.withinValidList());
+        return cursor.rangeForCurrentForm(0);                
     }
 
     rangesForTopLevelForms(): [number, number][] {