vim-patch:8.2.0867: using \{xxx} for encoding a modifier is not nice

Problem:    Using \{xxx} for encoding a modifier is not nice.
Solution:   Use \<*xxx> instead, since it's the same as \<xxx> but producing a
            different code.
fccd93f091

Use this notation in langmap_spec.

runtime/doc/eval.txt

@@ -1325,8 +1325,8 @@ A string constant accepts these special characters:
 	To use the double quote character it must be escaped: "<M-\">".
 	Don't use <Char-xxxx> to get a UTF-8 character, use \uxxxx as
 	mentioned above.
-\{xxx}	like \<xxx> but prepends a modifier instead of including it in the
-	character.  E.g. "\<C-w>" is one character 0x17 while "\{C-w}" is four
+\<*xxx>	Like \<xxx> but prepends a modifier instead of including it in the
+	character.  E.g. "\<C-w>" is one character 0x17 while "\<*C-w>" is four
 	bytes: 3 for the CTRL modifier and then character "W".
 
 Note that "\xff" is stored as the byte 255, which may be invalid in some

src/nvim/eval.c

@@ -4963,15 +4963,12 @@ static int get_string_tv(char_u **arg, typval_T *rettv, int evaluate)
         ++name;
         break;
 
-      // Special key, e.g.: "\<C-W>" or "\{C-W}"
-      case '<':
-      case '{': {
+      // Special key, e.g.: "\<C-W>"
+      case '<': {
         int flags = FSK_KEYCODE | FSK_IN_STRING;
 
-        if (*p == '<') {
+        if (p[1] != '*') {
           flags |= FSK_SIMPLIFY;
-        } else {
-          flags |= FSK_CURLY;
         }
         extra = trans_special((const char_u **)&p, STRLEN(p), name, flags, NULL);
         if (extra != 0) {

src/nvim/keymap.c

@@ -638,7 +638,6 @@ int find_special_key(const char_u **const srcp, const size_t src_len, int *const
   int modifiers;
   int bit;
   int key;
-  const int endchar = (flags & FSK_CURLY) ? '}' : '>';
   uvarnumber_T n;
   int l;
 
@@ -647,9 +646,12 @@ int find_special_key(const char_u **const srcp, const size_t src_len, int *const
   }
 
   src = *srcp;
-  if (src[0] != ((flags & FSK_CURLY) ? '{' : '<')) {
+  if (src[0] != '<') {
     return 0;
   }
+  if (src[1] == '*') {  // <*xxx>: do not simplify
+    src++;
+  }
 
   // Find end of modifier list
   last_dash = src;
@@ -661,16 +663,16 @@ int find_special_key(const char_u **const srcp, const size_t src_len, int *const
         // Anything accepted, like <C-?>.
         // <C-"> or <M-"> are not special in strings as " is
         // the string delimiter. With a backslash it works: <M-\">
-        if (end - bp > l && !(in_string && bp[1] == '"') && bp[l + 1] == endchar) {
+        if (end - bp > l && !(in_string && bp[1] == '"') && bp[l + 1] == '>') {
           bp += l;
         } else if (end - bp > 2 && in_string && bp[1] == '\\'
-                   && bp[2] == '"' && bp[3] == endchar) {
+                   && bp[2] == '"' && bp[3] == '>') {
           bp += 2;
         }
       }
     }
     if (end - bp > 3 && bp[0] == 't' && bp[1] == '_') {
-      bp += 3;  // skip t_xx, xx may be '-' or '>'/'}'
+      bp += 3;  // skip t_xx, xx may be '-' or '>'
     } else if (end - bp > 4 && STRNICMP(bp, "char-", 5) == 0) {
       vim_str2nr(bp + 5, NULL, &l, STR2NR_ALL, NULL, NULL, 0, true);
       if (l == 0) {
@@ -682,7 +684,7 @@ int find_special_key(const char_u **const srcp, const size_t src_len, int *const
     }
   }
 
-  if (bp <= end && *bp == endchar) {  // found matching '>' or '}'
+  if (bp <= end && *bp == '>') {  // found matching '>'
     end_of_name = bp + 1;
 
     // Which modifiers are given?
@@ -718,7 +720,7 @@ int find_special_key(const char_u **const srcp, const size_t src_len, int *const
         } else {
           l = utfc_ptr2len(last_dash + 1);
         }
-        if (modifiers != 0 && last_dash[l + 1] == endchar) {
+        if (modifiers != 0 && last_dash[l + 1] == '>') {
           key = utf_ptr2char(last_dash + off);
         } else {
           key = get_special_key_code(last_dash + off);

src/nvim/keymap.h

@@ -521,7 +521,6 @@ enum {
   FSK_KEEP_X_KEY = 0x02,  ///< don’t translate xHome to Home key
   FSK_IN_STRING  = 0x04,  ///< in string, double quote is escaped
   FSK_SIMPLIFY   = 0x08,  ///< simplify <C-H>, etc.
-  FSK_CURLY      = 0x10,  ///< {C-x} instead of <C-x>
 };
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS

src/nvim/testdir/test_backspace_opt.vim

@@ -76,7 +76,7 @@ func Test_backspace_ctrl_u()
 
   set cpo-=<
   inoremap <c-u> <left><c-u>
-  exe "normal Avim3\{C-U}\<Esc>\<CR>"
+  exe "normal Avim3\<*C-U>\<Esc>\<CR>"
   iunmap <c-u>
   exe "normal Avim4\<C-U>\<C-U>\<Esc>\<CR>"
 
@@ -86,7 +86,7 @@ func Test_backspace_ctrl_u()
   exe "normal A vim6\<Esc>Azwei\<C-G>u\<C-U>\<Esc>\<CR>"
 
   inoremap <c-u> <left><c-u>
-  exe "normal A vim7\{C-U}\{C-U}\<Esc>\<CR>"
+  exe "normal A vim7\<*C-U>\<*C-U>\<Esc>\<CR>"
 
   call assert_equal([
         \ "1 this shouldn't be deleted",

src/nvim/testdir/test_mapping.vim

@@ -62,7 +62,7 @@ func Test_map_ctrl_c_insert()
   inoremap <c-c> <ctrl-c>
   cnoremap <c-c> dummy
   cunmap <c-c>
-  call feedkeys("GoTEST2: CTRL-C |\{C-C}A|\<Esc>", "xt")
+  call feedkeys("GoTEST2: CTRL-C |\<*C-C>A|\<Esc>", "xt")
   call assert_equal('TEST2: CTRL-C |<ctrl-c>A|', getline('$'))
   unmap! <c-c>
   set nomodified
@@ -71,7 +71,7 @@ endfunc
 func Test_map_ctrl_c_visual()
   " mapping of ctrl-c in Visual mode
   vnoremap <c-c> :<C-u>$put ='vmap works'
-  call feedkeys("GV\{C-C}\<CR>", "xt")
+  call feedkeys("GV\<*C-C>\<CR>", "xt")
   call assert_equal('vmap works', getline('$'))
   vunmap <c-c>
   set nomodified
@@ -221,7 +221,7 @@ endfunc
 
 func Test_map_meta_quotes()
   imap <M-"> foo
-  call feedkeys("Go-\{M-\"}-\<Esc>", "xt")
+  call feedkeys("Go-\<*M-\">-\<Esc>", "xt")
   call assert_equal("-foo-", getline('$'))
   set nomodified
   iunmap <M-">

src/nvim/testdir/test_messages.vim

@@ -115,7 +115,7 @@ endfunc
 func Test_mapping_at_hit_return_prompt()
   nnoremap <C-B> :echo "hit ctrl-b"<CR>
   call feedkeys(":ls\<CR>", "xt")
-  call feedkeys("\{C-B}", "xt")
+  call feedkeys("\<*C-B>", "xt")
   call assert_match('hit ctrl-b', Screenline(&lines - 1))
   nunmap <C-B>
 endfunc

src/nvim/viml/parser/expressions.c

@@ -1815,15 +1815,12 @@ static void parse_quoted_string(ParserState *const pstate, ExprASTNode *const no
           *v_p++ = (char)ch;
           break;
         }
-        // Special key, e.g.: "\<C-W>" or "\{C-W}"
-        case '<':
-        case '{': {
+        // Special key, e.g.: "\<C-W>"
+        case '<': {
           int flags = FSK_KEYCODE | FSK_IN_STRING;
 
-          if (*p == '<') {
+          if (p[1] != '*') {
             flags |= FSK_SIMPLIFY;
-          } else {
-            flags |= FSK_CURLY;
           }
           const size_t special_len = trans_special((const char_u **)&p, (size_t)(e - p),
                                                    (char_u *)v_p, flags, NULL);

test/functional/editor/langmap_spec.lua

@@ -213,11 +213,11 @@ describe("'langmap'", function()
     iii]])
   end)
 
-  local function testrecording(command_string, expect_string, setup_function)
+  local function testrecording(command_string, expect_string, setup_function, expect_macro)
     if setup_function then setup_function() end
     feed('qa' .. command_string .. 'q')
     expect(expect_string)
-    eq(helpers.funcs.nvim_replace_termcodes(command_string, true, true, true),
+    eq(expect_macro or helpers.funcs.nvim_replace_termcodes(command_string, true, true, true),
       eval('@a'))
     if setup_function then setup_function() end
     -- n.b. may need nvim_replace_termcodes() here.
@@ -273,8 +273,8 @@ describe("'langmap'", function()
   it('treats control modified keys as characters', function()
     command('nnoremap <C-w> iw<esc>')
     command('nnoremap <C-i> ii<esc>')
-    testrecording('<C-w>', 'whello', local_setup)
-    testrecording('<C-i>', 'ihello', local_setup)
+    testrecording('<C-w>', 'whello', local_setup, eval([["\<*C-w>"]]))
+    testrecording('<C-i>', 'ihello', local_setup, eval([["\<*C-i>"]]))
   end)
 
 end)