Implement rot13 cypher (#179)

* implement rot13 cypher

* added tests

* fix one testcase

* fix g? testcase

Author: Opisek

src/vim.js

@@ -179,6 +179,7 @@ export function initVim(CodeMirror) {
     { keys: 'gN', type: 'motion', motion: 'findAndSelectNextInclusive', motionArgs: { forward: false }},
     { keys: 'gq', type: 'operator', operator: 'hardWrap' },
     { keys: 'gw', type: 'operator', operator: 'hardWrap', operatorArgs: {keepCursor: true}},
+    { keys: 'g?', type: 'operator', operator: 'rot13'},
     // Operator-Motion dual commands
     { keys: 'x', type: 'operatorMotion', operator: 'delete', motion: 'moveByCharacters', motionArgs: { forward: true }, operatorMotionArgs: { visualLine: false }},
     { keys: 'X', type: 'operatorMotion', operator: 'delete', motion: 'moveByCharacters', motionArgs: { forward: false }, operatorMotionArgs: { visualLine: true }},
@@ -2729,7 +2730,37 @@ export function initVim(CodeMirror) {
           args.registerName, 'yank',
           text, args.linewise, vim.visualBlock);
       return endPos;
-    }
+    },
+    rot13: function(cm, args, ranges, oldAnchor, newHead) {
+      var selections = cm.getSelections();
+      var swapped = [];
+      for (var j = 0; j < selections.length; j++) {
+        const replacement = selections[j]
+          .split('')
+          .map(x => {
+            const code = x.charCodeAt(0);
+            if (code >= 65 && code <= 90) { // Uppercase
+              return String.fromCharCode(65 + ((code - 65 + 13) % 26))
+            } else if (code >= 97 && code <= 122) { // Lowercase
+              return String.fromCharCode(97 + ((code - 97 + 13) % 26))
+            } else { // Not a letter
+              return x;
+            }
+          })
+          .join('')
+        swapped.push(replacement);
+      }
+      cm.replaceSelections(swapped);
+      if (args.shouldMoveCursor){
+        return newHead;
+      } else if (!cm.state.vim.visualMode && args.linewise && ranges[0].anchor.line + 1 == ranges[0].head.line) {
+        return motions.moveToFirstNonWhiteSpaceCharacter(cm, oldAnchor);
+      } else if (args.linewise){
+        return oldAnchor;
+      } else {
+        return cursorMin(ranges[0].anchor, ranges[0].head);
+      }
+    },
   };
 
   /** @arg {string} name  @arg {import("./types").OperatorFn} fn */

test/vim_test.js

@@ -1386,6 +1386,44 @@ testVim('gu_and_gU', function(cm, vim, helpers) {
   helpers.doKeys('g', 'U', '2', 'U');
   eq(cm.getValue(), 'ABC EFG\nXYZ');
 }, { value: 'wa wb xx wc wd' });
+testVim('g?', function(cm, vim, helpers) {
+  var curStart = makeCursor(0, 7);
+  var value = cm.getValue();
+  cm.setCursor(curStart);
+  helpers.doKeys('2', 'g', '?', 'w');
+  eq(cm.getValue(), 'wa wb xk jp wd');
+  eqCursorPos(curStart, cm.getCursor());
+  helpers.doKeys('2', 'g', '?', 'w');
+  eq(cm.getValue(), value);
+
+  helpers.doKeys('2', 'g', '?', 'B');
+  eq(cm.getValue(), 'wa jo kx wc wd');
+  eqCursorPos(makeCursor(0, 3), cm.getCursor());
+
+  cm.setCursor(makeCursor(0, 4));
+  helpers.doKeys('g', '?', 'i', 'w');
+  eq(cm.getValue(), 'wa wb kx wc wd');
+  eqCursorPos(makeCursor(0, 3), cm.getCursor());
+
+  var register = helpers.getRegisterController().getRegister();
+  eq('', register.toString());
+  is(!register.linewise);
+  
+  cm.setCursor(curStart);
+  cm.setValue('abc efg();\nxyz');
+  helpers.doKeys('g', '?', 'g', '?');
+  eq(cm.getValue(), 'nop rst();\nxyz');
+  helpers.doKeys('g', '?', '?');
+  eq(cm.getValue(), 'abc efg();\nxyz');
+  eqCursorPos(makeCursor(0, 0), cm.getCursor());
+  helpers.doKeys('g', '?', '2', '?');
+  eq(cm.getValue(), 'nop rst();\nklm');
+
+  cm.setCursor(curStart);
+  cm.setValue('hello\nworld');
+  helpers.doKeys('l','<C-v>','l','j','g','?');
+  eq(cm.getValue(), 'hrylo\nwbeld');
+}, { value: 'wa wb xx wc wd' });
 testVim('visual_block_~', function(cm, vim, helpers) {
   cm.setCursor(1, 1);
   helpers.doKeys('<C-v>', 'l', 'l', 'j', '~');