'keywordprg': support ex commands

- new feature: if the first character of 'keywordprg' is ":", the
  command is invoked as a Vim ex-command prefixed with [count].
- change default 'keywordprg' to :Man

runtime/doc/options.txt

@@ -3877,18 +3877,20 @@ A jump table for the options with a short description can be found at |Q_op|.
 	The 'keymodel' option is set by the |:behave| command.
 
 					*'keywordprg'* *'kp'*
-'keywordprg' 'kp'	string	(default "man" or "man -s",  DOS: ":help")
+'keywordprg' 'kp'	string	(default ":Man", Windows: ":help")
 			global or local to buffer |global-local|
 	Program to use for the |K| command.  Environment variables are
 	expanded |:set_env|.  ":help" may be used to access the Vim internal
 	help.  (Note that previously setting the global option to the empty
 	value did this, which is now deprecated.)
-	When "man" is used, Vim will automatically translate a count for the
+	When the first character is ":", the command is invoked as a Vim
-	"K" command to a section number.  Also for "man -s", in which case the
+	command prefixed with [count]. {Nvim}
-	"-s" is removed when there is no count.
+	When "man" or "man -s" is used, Vim will automatically translate
+	a [count] for the "K" command to a section number.
 	See |option-backslash| about including spaces and backslashes.
 	Example: >
 		:set keywordprg=man\ -s
+		:set keywordprg=:Man
 <	This option cannot be set from a |modeline| or in the |sandbox|, for
 	security reasons.
 

runtime/doc/various.txt

@@ -542,7 +542,7 @@ which it was defined is reported.
 {not available when compiled without the |+eval| feature}
 
 							*K*
-K			Run a program to lookup the keyword under the
+[count]K       		Run a program to lookup the keyword under the
 			cursor.  The name of the program is given with the
 			'keywordprg' (kp) option (default is "man").  The
 			keyword is formed of letters, numbers and the
@@ -550,19 +550,18 @@ K			Run a program to lookup the keyword under the
 			right of the cursor is used.  The same can be done
 			with the command >
 				:!{program} {keyword}
-<			There is an example of a program to use in the tools
+<			Special cases:
-			directory of Vim.  It is called 'ref' and does a
+			- If 'keywordprg' begins with ":" it is invoked as
-			simple spelling check.
+			  a Vim command with [count].
-			Special cases:
 			- If 'keywordprg' is empty, the ":help" command is
 			  used.  It's a good idea to include more characters
 			  in 'iskeyword' then, to be able to find more help.
-			- When 'keywordprg' is equal to "man", a count before
+			- When 'keywordprg' is equal to "man", a [count]
-			  "K" is inserted after the "man" command and before
+			  before "K" is inserted after the "man" command and
-			  the keyword.  For example, using "2K" while the
+			  before the keyword.  For example, using "2K" while
-			  cursor is on "mkdir", results in: >
+			  the cursor is on "mkdir", results in: >
 				!man 2 mkdir
-<			- When 'keywordprg' is equal to "man -s", a count
+<			- When 'keywordprg' is equal to "man -s", a [count]
 			  before "K" is inserted after the "-s".  If there is
 			  no count, the "-s" is removed.
 

runtime/ftplugin/man.vim

@@ -120,7 +120,7 @@ func <SID>GetPage(...)
     let sect = ""
   endif
   if s:FindPage(sect, page) == 0
-    echo "\nCannot find a '".page."'."
+    echo "\nNo manual entry for '".page."'."
     return
   endif
   exec "let s:man_tag_buf_".s:man_tag_depth." = ".bufnr("%")

src/nvim/normal.c

@@ -4213,18 +4213,12 @@ void do_nv_ident(int c1, int c2)
 static void nv_ident(cmdarg_T *cap)
 {
   char_u      *ptr = NULL;
-  char_u      *buf;
-  char_u      *newbuf;
   char_u      *p;
-  char_u      *kp;              /* value of 'keywordprg' */
-  bool kp_help;                 /* 'keywordprg' is ":help" */
   size_t n = 0;                 /* init for GCC */
   int cmdchar;
   bool g_cmd;                   /* "g" command */
   bool tag_cmd = false;
   char_u      *aux_ptr;
-  bool isman;
-  bool isman_s;
 
   if (cap->cmdchar == 'g') {    /* "g*", "g#", "g]" and "gCTRL-]" */
     cmdchar = cap->nchar;
@@ -4259,10 +4253,10 @@ static void nv_ident(cmdarg_T *cap)
   /* Allocate buffer to put the command in.  Inserting backslashes can
    * double the length of the word.  p_kp / curbuf->b_p_kp could be added
    * and some numbers. */
-  kp = (*curbuf->b_p_kp == NUL ? p_kp : curbuf->b_p_kp);
+  char_u *kp = (*curbuf->b_p_kp == NUL ? p_kp : curbuf->b_p_kp);  //'keywordprg'
-  kp_help = (*kp == NUL || STRCMP(kp, ":he") == 0
+  assert(*kp != NUL);  //option.c::do_set() should default to ":help" if empty.
-             || STRCMP(kp, ":help") == 0);
+  bool kp_ex = (*kp == ':');  //'keywordprg' is an ex command
-  buf = xmalloc(n * 2 + 30 + STRLEN(kp));
+  char *buf = xmalloc(n * 2 + 30 + STRLEN(kp));
   buf[0] = NUL;
 
   switch (cmdchar) {
@@ -4283,9 +4277,13 @@ static void nv_ident(cmdarg_T *cap)
     break;
 
   case 'K':
-    if (kp_help)
+    if (kp_ex) {
-      STRCPY(buf, "he! ");
+      if (cap->count0 != 0) {  // Send the count to the ex command.
-    else {
+        sprintf(buf, "%" PRId64, (int64_t)(cap->count0));
+      }
+      STRCAT(buf, kp);
+      STRCAT(buf, " ");
+    } else {
       /* An external command will probably use an argument starting
        * with "-" as an option.  To avoid trouble we skip the "-". */
       while (*ptr == '-' && n > 0) {
@@ -4300,10 +4298,10 @@ static void nv_ident(cmdarg_T *cap)
 
       /* When a count is given, turn it into a range.  Is this
        * really what we want? */
-      isman = (STRCMP(kp, "man") == 0);
+      bool isman = (STRCMP(kp, "man") == 0);
-      isman_s = (STRCMP(kp, "man -s") == 0);
+      bool isman_s = (STRCMP(kp, "man -s") == 0);
       if (cap->count0 != 0 && !(isman || isman_s))
-        sprintf((char *)buf, ".,.+%" PRId64, (int64_t)(cap->count0 - 1));
+        sprintf(buf, ".,.+%" PRId64, (int64_t)(cap->count0 - 1));
 
       STRCAT(buf, "! ");
       if (cap->count0 == 0 && isman_s)
@@ -4312,7 +4310,7 @@ static void nv_ident(cmdarg_T *cap)
         STRCAT(buf, kp);
       STRCAT(buf, " ");
       if (cap->count0 != 0 && (isman || isman_s)) {
-        sprintf((char *)buf + STRLEN(buf), "%" PRId64, (int64_t)cap->count0);
+        sprintf(buf + STRLEN(buf), "%" PRId64, (int64_t)cap->count0);
         STRCAT(buf, " ");
       }
     }
@@ -4334,19 +4332,19 @@ static void nv_ident(cmdarg_T *cap)
       if (g_cmd)
         STRCPY(buf, "tj ");
       else
-        sprintf((char *)buf, "%" PRId64 "ta ", (int64_t)cap->count0);
+        sprintf(buf, "%" PRId64 "ta ", (int64_t)cap->count0);
     }
   }
 
   /*
    * Now grab the chars in the identifier
    */
-  if (cmdchar == 'K' && !kp_help) {
+  if (cmdchar == 'K' && !kp_ex) {
     /* Escape the argument properly for a shell command */
     ptr = vim_strnsave(ptr, n);
     p = vim_strsave_shellescape(ptr, true, true);
     xfree(ptr);
-    newbuf = (char_u *)xrealloc(buf, STRLEN(buf) + STRLEN(p) + 1);
+    char *newbuf = xrealloc(buf, STRLEN(buf) + STRLEN(p) + 1);
     buf = newbuf;
     STRCAT(buf, p);
     xfree(p);
@@ -4364,7 +4362,7 @@ static void nv_ident(cmdarg_T *cap)
     } else
       aux_ptr = (char_u *)"\\|\"\n*?[";
 
-    p = buf + STRLEN(buf);
+    p = (char_u *)buf + STRLEN(buf);
     while (n-- > 0) {
       /* put a backslash before \ and some others */
       if (vim_strchr(aux_ptr, *ptr) != NULL)
@@ -4391,10 +4389,10 @@ static void nv_ident(cmdarg_T *cap)
       STRCAT(buf, "\\>");
     /* put pattern in search history */
     init_history();
-    add_to_history(HIST_SEARCH, buf, true, NUL);
+    add_to_history(HIST_SEARCH, (char_u *)buf, true, NUL);
-    (void)normal_search(cap, cmdchar == '*' ? '/' : '?', buf, 0);
+    (void)normal_search(cap, cmdchar == '*' ? '/' : '?', (char_u *)buf, 0);
   } else
-    do_cmdline_cmd((char *)buf);
+    do_cmdline_cmd(buf);
 
   xfree(buf);
 }

src/nvim/options.lua

@@ -1329,7 +1329,7 @@ return {
       expand=true,
       varname='p_kp',
       defaults={
-        if_true={vi="man -s"},
+        if_true={vi=":Man"},
       }
     },
     {