vim-patch:9.1.1408: not easily possible to complete from register content (#34198)

Problem:  not easily possible to complete from register content
Solution: add register-completion submode using i_CTRL-X_CTRL-R
          (glepnir)

closes: vim/vim#17354

0546068aae

runtime/doc/index.txt

@@ -146,6 +146,7 @@ commands in CTRL-X submode				*i_CTRL-X_index*
 |i_CTRL-X_CTRL-N|	CTRL-X CTRL-N	next completion
 |i_CTRL-X_CTRL-O|	CTRL-X CTRL-O	omni completion
 |i_CTRL-X_CTRL-P|	CTRL-X CTRL-P	previous completion
+|i_CTRL-X_CTRL-R|	CTRL-X CTRL-R	complete words from registers
 |i_CTRL-X_CTRL-S|	CTRL-X CTRL-S	spelling suggestions
 |i_CTRL-X_CTRL-T|	CTRL-X CTRL-T	complete identifiers from thesaurus
 |i_CTRL-X_CTRL-Y|	CTRL-X CTRL-Y	scroll down

runtime/doc/insert.txt

@@ -629,6 +629,7 @@ Completion can be done for:
 11. omni completion					|i_CTRL-X_CTRL-O|
 12. Spelling suggestions				|i_CTRL-X_s|
 13. keywords in 'complete'				|i_CTRL-N| |i_CTRL-P|
+14. words from registers				|i_CTRL-X_CTRL-R|
 
 Additionally, |i_CTRL-X_CTRL-Z| stops completion without changing the text.
 
@@ -999,6 +1000,20 @@ CTRL-X CTRL-V		Guess what kind of item is in front of the cursor and
 			completion, for example: >
 				:imap <Tab> <C-X><C-V>
 
+Completing words from registers				*compl-register-words*
+							*i_CTRL-X_CTRL-R*
+CTRL-X CTRL-R		Guess what kind of item is in front of the cursor from
+			all registers and find the first match for it.
+			Further use of CTRL-R (without CTRL-X) will insert the
+			register content, see |i_CTRL-R|.
+			'ignorecase' applies to the matching.
+
+	CTRL-N		Search forwards for next match.  This match replaces
+			the previous one.
+
+	CTRL-P		Search backwards for previous match.  This match
+			replaces the previous one.
+
 User defined completion					*compl-function*
 
 Completion is done by a function that can be defined by the user with the

runtime/doc/options.txt

@@ -3345,7 +3345,8 @@ A jump table for the options with a short description can be found at |Q_op|.
 'ignorecase' 'ic'	boolean	(default off)
 			global
 	Ignore case in search patterns, |cmdline-completion|, when
-	searching in the tags file, and |expr-==|.
+	searching in the tags file, |expr-==| and for Insert-mode completion
+	|ins-completion|.
 	Also see 'smartcase' and 'tagcase'.
 	Can be overruled by using "\c" or "\C" in the pattern, see
 	|/ignorecase|.

runtime/doc/usr_24.txt

@@ -187,6 +187,7 @@ with a certain type of item:
 	CTRL-X CTRL-D		macro definitions (also in included files)
 	CTRL-X CTRL-I		current and included files
 	CTRL-X CTRL-K		words from a dictionary
+	CTRL-X CTRL-R		words from registers
 	CTRL-X CTRL-T		words from a thesaurus
 	CTRL-X CTRL-]		tags
 	CTRL-X CTRL-V		Vim command line

runtime/doc/vi_diff.txt

@@ -230,6 +230,7 @@ Insert-mode completion.					|ins-completion|
 	|i_CTRL-X_CTRL-D|	definitions or macros
 	|i_CTRL-X_CTRL-O|	Omni completion: clever completion
 				specifically for a file type
+	|i_CTRL-X_CTRL-R|	words from registers
 	etc.
 
 Long line support.					|'wrap'| |'linebreak'|

runtime/lua/vim/_meta/options.lua

@@ -3186,7 +3186,8 @@ vim.o.iconstring = ""
 vim.go.iconstring = vim.o.iconstring
 
 --- Ignore case in search patterns, `cmdline-completion`, when
---- searching in the tags file, and `expr-==`.
+--- searching in the tags file, `expr-==` and for Insert-mode completion
+--- `ins-completion`.
 --- Also see 'smartcase' and 'tagcase'.
 --- Can be overruled by using "\c" or "\C" in the pattern, see
 --- `/ignorecase`.

src/nvim/edit.c

@@ -796,6 +796,10 @@ static int insert_handle_key(InsertState *s)
     break;
 
   case Ctrl_R:        // insert the contents of a register
+    if (ctrl_x_mode_register() && !ins_compl_active()) {
+      insert_do_complete(s);
+      break;
+    }
     ins_reg();
     auto_format(false, true);
     s->inserted_space = false;

src/nvim/insexpand.c

@@ -53,6 +53,7 @@
 #include "nvim/memory.h"
 #include "nvim/message.h"
 #include "nvim/move.h"
+#include "nvim/ops.h"
 #include "nvim/option.h"
 #include "nvim/option_defs.h"
 #include "nvim/option_vars.h"
@@ -104,6 +105,7 @@ enum {
   CTRL_X_EVAL = 16,            ///< for builtin function complete()
   CTRL_X_CMDLINE_CTRL_X = 17,  ///< CTRL-X typed in CTRL_X_CMDLINE
   CTRL_X_BUFNAMES = 18,
+  CTRL_X_REGISTER = 19,        ///< complete words from registers
 };
 
 #define CTRL_X_MSG(i) ctrl_x_msgs[(i) & ~CTRL_X_WANT_IDENT]
@@ -111,7 +113,7 @@ enum {
 /// Message for CTRL-X mode, index is ctrl_x_mode.
 static char *ctrl_x_msgs[] = {
   N_(" Keyword completion (^N^P)"),  // CTRL_X_NORMAL, ^P/^N compl.
-  N_(" ^X mode (^]^D^E^F^I^K^L^N^O^Ps^U^V^Y)"),
+  N_(" ^X mode (^]^D^E^F^I^K^L^N^O^P^Rs^U^V^Y)"),
   NULL,  // CTRL_X_SCROLL: depends on state
   N_(" Whole line completion (^L^N^P)"),
   N_(" File name completion (^F^N^P)"),
@@ -128,6 +130,8 @@ static char *ctrl_x_msgs[] = {
   N_(" Keyword Local completion (^N^P)"),
   NULL,  // CTRL_X_EVAL doesn't use msg.
   N_(" Command-line completion (^V^N^P)"),
+  NULL,
+  N_(" Register completion (^N^P)"),
 };
 
 static char *ctrl_x_mode_names[] = {
@@ -149,6 +153,8 @@ static char *ctrl_x_mode_names[] = {
   NULL,               // CTRL_X_LOCAL_MSG only used in "ctrl_x_msgs"
   "eval",
   "cmdline",
+  NULL,               // CTRL_X_BUFNAME
+  "register",
 };
 
 /// Structure used to store one match for insert completion.
@@ -423,6 +429,12 @@ bool ctrl_x_mode_line_or_eval(void)
   return ctrl_x_mode == CTRL_X_WHOLE_LINE || ctrl_x_mode == CTRL_X_EVAL;
 }
 
+bool ctrl_x_mode_register(void)
+  FUNC_ATTR_PURE
+{
+  return ctrl_x_mode == CTRL_X_REGISTER;
+}
+
 /// Whether other than default completion has been selected.
 bool ctrl_x_mode_not_default(void)
   FUNC_ATTR_PURE
@@ -514,7 +526,7 @@ bool vim_is_ctrl_x_key(int c)
   FUNC_ATTR_WARN_UNUSED_RESULT
 {
   // Always allow ^R - let its results then be checked
-  if (c == Ctrl_R) {
+  if (c == Ctrl_R && ctrl_x_mode != CTRL_X_REGISTER) {
     return true;
   }
 
@@ -534,7 +546,7 @@ bool vim_is_ctrl_x_key(int c)
            || c == Ctrl_N || c == Ctrl_T || c == Ctrl_V
            || c == Ctrl_Q || c == Ctrl_U || c == Ctrl_O
            || c == Ctrl_S || c == Ctrl_K || c == 's'
-           || c == Ctrl_Z;
+           || c == Ctrl_Z || c == Ctrl_R;
   case CTRL_X_SCROLL:
     return c == Ctrl_Y || c == Ctrl_E;
   case CTRL_X_WHOLE_LINE:
@@ -564,6 +576,8 @@ bool vim_is_ctrl_x_key(int c)
     return (c == Ctrl_P || c == Ctrl_N);
   case CTRL_X_BUFNAMES:
     return (c == Ctrl_P || c == Ctrl_N);
+  case CTRL_X_REGISTER:
+    return (c == Ctrl_R || c == Ctrl_P || c == Ctrl_N);
   }
   internal_error("vim_is_ctrl_x_key()");
   return false;
@@ -2244,8 +2258,12 @@ static bool set_ctrl_x_mode(const int c)
     ctrl_x_mode = CTRL_X_DICTIONARY;
     break;
   case Ctrl_R:
-    // Register insertion without exiting CTRL-X mode
+    // When CTRL-R is followed by '=', don't trigger register completion
-    // Simply allow ^R to happen without affecting ^X mode
+    // This allows expressions like <C-R>=func()<CR> to work normally
+    if (vpeekc() == '=') {
+      break;
+    }
+    ctrl_x_mode = CTRL_X_REGISTER;
     break;
   case Ctrl_T:
     // complete words from a thesaurus
@@ -4027,6 +4045,63 @@ static int get_next_default_completion(ins_compl_next_state_T *st, pos_T *start_
   return found_new_match;
 }
 
+/// Get completion matches from register contents.
+/// Extracts words from all available registers and adds them to the completion list.
+static void get_register_completion(void)
+{
+  Direction dir = compl_direction;
+
+  for (int i = 0; i < NUM_REGISTERS; i++) {
+    int regname = get_register_name(i);
+    // Skip invalid or black hole register
+    if (!valid_yank_reg(regname, false) || regname == '_') {
+      continue;
+    }
+
+    yankreg_T *reg = copy_register(regname);
+
+    if (reg->y_array == NULL || reg->y_size == 0) {
+      free_register(reg);
+      xfree(reg);
+      continue;
+    }
+
+    for (size_t j = 0; j < reg->y_size; j++) {
+      char *str = reg->y_array[j].data;
+      if (str == NULL) {
+        continue;
+      }
+
+      char *p = str;
+      while (*p != NUL) {
+        p = find_word_start(p);
+        if (*p == NUL) {
+          break;
+        }
+
+        char *word_end = find_word_end(p);
+        int len = (int)(word_end - p);
+
+        // Add the word to the completion list
+        if (len > 0 && (!compl_orig_text.data
+                        || (p_ic ? STRNICMP(p, compl_orig_text.data,
+                                            compl_orig_text.size) == 0
+                                 : strncmp(p, compl_orig_text.data,
+                                           compl_orig_text.size) == 0))) {
+          if (ins_compl_add_infercase(p, len, p_ic, NULL,
+                                      dir, false, 0) == OK) {
+            dir = FORWARD;
+          }
+        }
+        p = word_end;
+      }
+    }
+
+    free_register(reg);
+    xfree(reg);
+  }
+}
+
 /// get the next set of completion matches for "type".
 /// @return  true if a new match is found, otherwise false.
 static bool get_next_completion_match(int type, ins_compl_next_state_T *st, pos_T *ini)
@@ -4071,6 +4146,9 @@ static bool get_next_completion_match(int type, ins_compl_next_state_T *st, pos_
   case CTRL_X_BUFNAMES:
     get_next_bufname_token();
     break;
+  case CTRL_X_REGISTER:
+    get_register_completion();
+    break;
 
   default:            // normal ^P/^N and ^X^L
     found_new_match = get_next_default_completion(st, ini);
@@ -5077,6 +5155,8 @@ static int compl_get_info(char *line, int startcol, colnr_T curs_col, bool *line
       return FAIL;
     }
     *line_invalid = true;  // "line" may have become invalid
+  } else if (ctrl_x_mode_register()) {
+    return get_normal_compl_info(line, startcol, curs_col);
   } else {
     internal_error("ins_complete()");
     return FAIL;

src/nvim/options.lua

@@ -4315,7 +4315,8 @@ local options = {
       defaults = false,
       desc = [=[
         Ignore case in search patterns, |cmdline-completion|, when
-        searching in the tags file, and |expr-==|.
+        searching in the tags file, |expr-==| and for Insert-mode completion
+        |ins-completion|.
         Also see 'smartcase' and 'tagcase'.
         Can be overruled by using "\c" or "\C" in the pattern, see
         |/ignorecase|.

test/functional/editor/completion_spec.lua

@@ -124,7 +124,7 @@ describe('completion', function()
         foo                                                         |
         ^                                                            |
         {1:~                                                           }|*5
-        {5:-- ^X mode (^]^D^E^F^I^K^L^N^O^Ps^U^V^Y)}                    |
+        {5:-- ^X mode (^]^D^E^F^I^K^L^N^O^P^Rs^U^V^Y)}                  |
       ]])
       feed('<C-n>')
       screen:expect([[

test/functional/ui/float_spec.lua

@@ -3519,7 +3519,7 @@ describe('float window', function()
                                                             |
           {0:~                                                 }|*7
         ## grid 3
-          {3:-- ^X mode (^]^D^E^F^I^K^L^N^O^Ps^U^V^Y)}          |
+          {3:-- ^X mode (^]^D^E^F^I^K^L^N^O^P^Rs^U^V^Y)}        |
         ## grid 4
           {1:   }|
           {2:~  }|*2
@@ -3543,7 +3543,7 @@ describe('float window', function()
           {1:   }  {1:^   }                                          |
           {2:~  }{0:  }{2:~  }{0:                                          }|*2
           {0:~                                                 }|*5
-          {3:-- ^X mode (^]^D^E^F^I^K^L^N^O^Ps^U^V^Y)}          |
+          {3:-- ^X mode (^]^D^E^F^I^K^L^N^O^P^Rs^U^V^Y)}        |
         ]],
         }
       end

test/functional/ui/messages_spec.lua

@@ -815,7 +815,7 @@ describe('ui/ext_messages', function()
       ^                         |
       {1:~                        }|*2
     ]],
-      showmode = { { '-- ^X mode (^]^D^E^F^I^K^L^N^O^Ps^U^V^Y)', 5, 11 } },
+      showmode = { { '-- ^X mode (^]^D^E^F^I^K^L^N^O^P^Rs^U^V^Y)', 5, 11 } },
     }
 
     feed('<c-p>')

test/old/testdir/test_ins_complete.vim

@@ -3792,4 +3792,85 @@ func Test_complete_match()
   delfunc TestComplete
 endfunc
 
+func Test_register_completion()
+  let @a = "completion test apple application"
+  let @b = "banana behavior better best"
+  let @c = "complete completion compliment computer"
+  let g:save_reg = ''
+  func GetItems()
+    let g:result = complete_info(['pum_visible'])
+  endfunc
+
+  new
+  call setline(1, "comp")
+  call cursor(1, 4)
+  call feedkeys("a\<C-X>\<C-R>\<C-N>\<C-N>\<Esc>", 'tx')
+  call assert_equal("compliment", getline(1))
+
+  inoremap <buffer><F2> <C-R>=GetItems()<CR>
+  call feedkeys("S\<C-X>\<C-R>\<F2>\<ESC>", 'tx')
+  call assert_equal(1, g:result['pum_visible'])
+
+  call setline(1, "app")
+  call cursor(1, 3)
+  call feedkeys("a\<C-X>\<C-R>\<C-N>\<Esc>", 'tx')
+  call assert_equal("application", getline(1))
+
+  " Test completion with case differences
+  set ignorecase
+  let @e = "TestCase UPPERCASE lowercase"
+  call setline(1, "testc")
+  call cursor(1, 5)
+  call feedkeys("a\<C-X>\<C-R>\<Esc>", 'tx')
+  call assert_equal("TestCase", getline(1))
+
+  " Test clipboard registers if available
+  if has('clipboard_working')
+    let g:save_reg = getreg('*')
+    call setreg('*', "clipboard selection unique words")
+    call setline(1, "uni")
+    call cursor(1, 3)
+    call feedkeys("a\<C-X>\<C-R>\<Esc>", 'tx')
+    call assert_equal("unique", getline(1))
+    call setreg('*', g:save_reg)
+
+    let g:save_reg = getreg('+')
+    call setreg('+', "system clipboard special content")
+    call setline(1, "spe")
+    call cursor(1, 3)
+    call feedkeys("a\<C-X>\<C-R>\<Esc>", 'tx')
+    call assert_equal("special", getline(1))
+    call setreg('+', g:save_reg)
+
+    call setreg('*', g:save_reg)
+    call setreg('a', "normal register")
+    call setreg('*', "clipboard mixed content")
+    call setline(1, "mix")
+    call cursor(1, 3)
+    call feedkeys("a\<C-X>\<C-R>\<Esc>", 'tx')
+    call assert_equal("mixed", getline(1))
+    call setreg('*', g:save_reg)
+  endif
+
+  " Test black hole register should be skipped
+  let @_ = "blackhole content should not appear"
+  call setline(1, "black")
+  call cursor(1, 5)
+  call feedkeys("a\<C-X>\<C-R>\<Esc>", 'tx')
+  call assert_equal("black", getline(1))
+
+  let @1 = "recent yank zero"
+  call setline(1, "ze")
+  call cursor(1, 2)
+  call feedkeys("a\<C-X>\<C-R>\<Esc>", 'tx')
+  call assert_equal("zero", getline(1))
+
+  " Clean up
+  bwipe!
+  delfunc GetItems
+  unlet g:result
+  unlet g:save_reg
+  set ignorecase&
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab nofoldenable