Merge pull request #1282 from splinterofchaos/cmd-undef

vim-patch:7.4.414 + vim-patch:7.4.415

runtime/doc/autocmd.txt

@@ -278,6 +278,7 @@ Name			triggered by ~
 |ShellCmdPost|		after executing a shell command
 |ShellFilterPost|	after filtering with a shell command
 
+|CmdUndefined|		a user command is used but it isn't defined
 |FuncUndefined|		a user function is used but it isn't defined
 |SpellFileMissing|	a spell file is used but it can't be found
 |SourcePre|		before sourcing a Vim script
@@ -466,6 +467,16 @@ BufWriteCmd			Before writing the whole buffer to a file.
 							*BufWritePost*
 BufWritePost			After writing the whole buffer to a file
 				(should undo the commands for BufWritePre).
+							*CmdUndefined*
+CmdUndefined			When a user command is used but it isn't
+				defined.  Useful for defining a command only
+				when it's used.  The pattern is matched
+				against the command name.  Both <amatch> and
+				<afile> are set to the name of the command.
+				NOTE: Autocompletion won't work until the
+				command is defined.  An alternative is to
+				always define the user command and have it
+				invoke an autoloaded function.  See |autoload|.
 							*CmdwinEnter*
 CmdwinEnter			After entering the command-line window.
 				Useful for setting options specifically for
@@ -671,6 +682,8 @@ FuncUndefined			When a user function is used but it isn't
 				when it's used.  The pattern is matched
 				against the function name.  Both <amatch> and
 				<afile> are set to the name of the function.
+				NOTE: When writing Vim scripts a better
+				alternative is to use an autoloaded function.
 				See |autoload-functions|.
 							*GUIEnter*
 GUIEnter			After starting the GUI successfully, and after

src/nvim/ex_docmd.c

@@ -1459,6 +1459,23 @@ static char_u * do_one_cmd(char_u **cmdlinep,
   /* Find the command and let "p" point to after it. */
   p = find_command(&ea, NULL);
 
+  // If this looks like an undefined user command and there are CmdUndefined
+  // autocommands defined, trigger the matching autocommands.
+  if (p != NULL && ea.cmdidx == CMD_SIZE && !ea.skip
+      && ASCII_ISUPPER(*ea.cmd)
+      && has_cmdundefined()) {
+    p = ea.cmd;
+    while (ASCII_ISALNUM(*p)) {
+      ++p;
+    }
+    p = vim_strnsave(ea.cmd, p - ea.cmd);
+    int ret = apply_autocmds(EVENT_CMDUNDEFINED, p, p, TRUE, NULL);
+    free(p);
+    if (ret && !aborting()) {
+      p = find_command(&ea, NULL);
+    }
+  }
+
   if (p == NULL) {
     if (!ea.skip)
       errormsg = (char_u *)_("E464: Ambiguous use of user-defined command");

src/nvim/fileio.c

@@ -72,25 +72,25 @@
  * The result is an array of Autopat lists, which point to AutoCmd lists:
  *
  * first_autopat[0] --> Autopat.next  -->  Autopat.next -->  NULL
- *			Autopat.cmds	   Autopat.cmds
+ *                      Autopat.cmds       Autopat.cmds
- *			    |			 |
+ *                          |                    |
- *			    V			 V
+ *                          V                    V
- *			AutoCmd.next	   AutoCmd.next
+ *                      AutoCmd.next       AutoCmd.next
- *			    |			 |
+ *                          |                    |
- *			    V			 V
+ *                          V                    V
- *			AutoCmd.next		NULL
+ *                      AutoCmd.next            NULL
- *			    |
+ *                          |
- *			    V
+ *                          V
- *			   NULL
+ *                         NULL
  *
  * first_autopat[1] --> Autopat.next  -->  NULL
- *			Autopat.cmds
+ *                      Autopat.cmds
- *			    |
+ *                          |
- *			    V
+ *                          V
- *			AutoCmd.next
+ *                      AutoCmd.next
- *			    |
+ *                          |
- *			    V
+ *                          V
- *			   NULL
+ *                         NULL
  *   etc.
  *
  *   The order of AutoCmds is important, this is the order in which they were
@@ -5198,6 +5198,7 @@ static struct event_name {
   {"BufWriteCmd",     EVENT_BUFWRITECMD},
   {"CmdwinEnter",     EVENT_CMDWINENTER},
   {"CmdwinLeave",     EVENT_CMDWINLEAVE},
+  {"CmdUndefined",    EVENT_CMDUNDEFINED},
   {"ColorScheme",     EVENT_COLORSCHEME},
   {"CompleteDone",    EVENT_COMPLETEDONE},
   {"CursorHold",      EVENT_CURSORHOLD},
@@ -6462,6 +6463,18 @@ int has_insertcharpre(void)
   return first_autopat[(int)EVENT_INSERTCHARPRE] != NULL;
 }
 
+/// @returns true when there is an CmdUndefined autocommand defined.
+int has_cmdundefined(void)
+{
+  return first_autopat[(int)EVENT_CMDUNDEFINED] != NULL;
+}
+
+/// @returns true when there is an FuncUndefined autocommand defined.
+int has_funcundefined(void)
+{
+  return first_autopat[(int)EVENT_FUNCUNDEFINED] != NULL;
+}
+
 static int 
 apply_autocmds_group (
     event_T event,

src/nvim/fileio.h

@@ -99,6 +99,7 @@ typedef enum auto_event {
   EVENT_SHELLFILTERPOST,        /* after ":1,2!cmd", ":w !cmd", ":r !cmd". */
   EVENT_TEXTCHANGED,            /* text was modified */
   EVENT_TEXTCHANGEDI,           /* text was modified in Insert mode*/
+  EVENT_CMDUNDEFINED,           ///< command undefined
   NUM_EVENTS                    /* MUST be the last one */
 } event_T;
 

src/nvim/version.c

@@ -250,8 +250,8 @@ static int included_patches[] = {
   418,
   //417,
   //416,
-  //415,
+  415,
-  //414,
+  414,
   //413 NA
   //412 NA
   411,