[vim] Add a non-recursive map command

This will allow for more powerful mapping capabilities like arbitrary command
remapping, rebinding the home row, etc.

This doesn't quite match Vim's non-recursive behavior because there's no support
for non-recursive keyToKey mappings. Without this support, we'd just be creating
normal, recursive keyToKey mappings which I think would be even more frustrating
and/or surprising (e.g. two inverse non-recursive maps would cause infinite recursion).
Once this support is added for this, though, it will be trivial to create these mappings
at the end of the added function and achieve the most accurate behavior.

One potential paper cut with this implementation is that multiple calls to `unmap` may
be required to fully remove the `noremap`ed values. I think this isn't that severe though
because this looks to be the current behavior with all other `map` operations.

Author: msuozzo

keymap/vim.js

@@ -3,7 +3,7 @@
 
 /**
  * Supported keybindings:
- *   Too many to list. Refer to defaultKeyMap below.
+ *   Too many to list. Refer to defaultKeymap below.
  *
  * Supported Ex commands:
  *   Refer to defaultExCommandMap below.
@@ -207,6 +207,7 @@
     // Ex command
     { keys: ':', type: 'ex' }
   ];
+  var defaultKeymapLength = defaultKeymap.length;
 
   /**
    * Ex commands
@@ -742,6 +743,44 @@
       unmap: function(lhs, ctx) {
         exCommandDispatcher.unmap(lhs, ctx);
       },
+      // Non-recursive map function.
+      // NOTE: This will not create mappings to key maps that aren't present
+      // in the default key map. See TODO at bottom of function.
+      noremap: function(lhs, rhs, ctx) {
+        function toCtxArray(ctx) {
+          return ctx ? [ctx] : ['normal', 'insert', 'visual'];
+        }
+        var ctxsToMap = toCtxArray(ctx);
+        // Look through all actual defaults to find a map candidate.
+        var actualLength = defaultKeymap.length, origLength = defaultKeymapLength;
+        for (var i = actualLength - origLength - 1;
+             i < actualLength && ctxsToMap.length;
+             i++) {
+          var mapping = defaultKeymap[i];
+          // Omit mappings that operate in the wrong context(s) and those of invalid type.
+          if (mapping.keys == rhs &&
+              (!ctx || !mapping.context || mapping.context === ctx) &&
+              mapping.type.substr(0, 2) !== 'ex' &&
+              mapping.type.substr(0, 3) !== 'key') {
+            // Make a shallow copy of the original keymap entry.
+            var newMapping = {};
+            for (var key in mapping) {
+              newMapping[key] = mapping[key];
+            }
+            // Modify it point to the new mapping with the proper context.
+            newMapping.keys = lhs;
+            if (ctx && !newMapping.context) {
+              newMapping.context = ctx;
+            }
+            // Add it to the keymap with a higher priority than the original.
+            this._mapCommand(newMapping);
+            // Record the mapped contexts as complete.
+            var mappedCtxs = toCtxArray(mapping.context);
+            ctxsToMap = ctxsToMap.filter(function(el) { return mappedCtxs.indexOf(el) === -1; });
+          }
+        }
+        // TODO: Create non-recursive keyToKey mappings for the unmapped contexts once those exist.
+      },
       // TODO: Expose setOption and getOption as instance methods. Need to decide how to namespace
       // them, or somehow make them work with the existing CodeMirror setOption/getOption API.
       setOption: setOption,

test/vim_test.js

@@ -4245,7 +4245,6 @@ testVim('ex_unmap_api', function(cm, vim, helpers) {
   CodeMirror.Vim.unmap("<Alt-X>", "normal");
   is(!CodeMirror.Vim.handleKey(cm, "<Alt-X>", "normal"), "Alt-X key is unmapped");
 });
-
 // Testing registration of functions as ex-commands and mapping to <Key>-keys
 testVim('ex_api_test', function(cm, vim, helpers) {
   var res=false;
@@ -4268,6 +4267,30 @@ testVim('ex_map_key2key_from_colon', function(cm, vim, helpers) {
   eq('bc', cm.getValue());
 }, { value: 'abc' });
 
+testVim('noremap', function(cm, vim, helpers) {
+  CodeMirror.Vim.noremap(';', 'l');
+  cm.setCursor(0, 0);
+  eq('wOrd1', cm.getValue());
+  // Mapping should work in normal mode.
+  helpers.doKeys(';', 'r', '1');
+  eq('w1rd1', cm.getValue());
+  // Mapping will not work in insert mode because of no current fallback
+  // keyToKey mapping support.
+  helpers.doKeys('i', ';', '<Esc>');
+  eq('w;1rd1', cm.getValue());
+}, { value: 'wOrd1' });
+testVim('noremap_swap', function(cm, vim, helpers) {
+  CodeMirror.Vim.noremap('i', 'a', 'normal');
+  CodeMirror.Vim.noremap('a', 'i', 'normal');
+  cm.setCursor(0, 0);
+  // 'a' should act like 'i'.
+  helpers.doKeys('a');
+  eqCursorPos(Pos(0, 0), cm.getCursor());
+  // ...and 'i' should act like 'a'.
+  helpers.doKeys('<Esc>', 'i');
+  eqCursorPos(Pos(0, 1), cm.getCursor());
+}, { value: 'foo' });
+
 // Test event handlers
 testVim('beforeSelectionChange', function(cm, vim, helpers) {
   cm.setCursor(0, 100);