Make set{qf,loc}list() take {title}

Add an extra argument to these functions to set w:quickfix_title.

This is a modified version of a patch from vim_dev. Discussion here:

  https://groups.google.com/forum/#!topic/vim_dev/X7VVPd4Do5s

Credits go to Christian "chrisbra" Brabandt and Daniel "blueyed" Hahler.

2 files changed, 48 insertions, 18 deletions

diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index 45980f5d94..5dbef81748 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -1999,11 +1999,12 @@ setbufvar( {expr}, {varname}, {val})	set {varname} in buffer {expr} to {val}
 setcharsearch( {dict})		Dict	set character search from {dict}
 setcmdpos( {pos})		Number	set cursor position in command-line
 setline( {lnum}, {line})	Number	set line {lnum} to {line}
-setloclist( {nr}, {list}[, {action}])
+setloclist( {nr}, {list}[, {action}[, {title}]])
 				Number	modify location list using {list}
 setmatches( {list})		Number	restore a list of matches
 setpos( {expr}, {list})		Number	set the {expr} position to {list}
-setqflist( {list}[, {action}])	Number	modify quickfix list using {list}
+setqflist( {list}[, {action}[, {title}]]
+				Number	modify quickfix list using {list}
 setreg( {n}, {v}[, {opt}])	Number	set register to value and type
 settabvar( {nr}, {varname}, {val})	set {varname} in tab page {nr} to {val}
 settabwinvar( {tabnr}, {winnr}, {varname}, {val})    set {varname} in window
@@ -5732,11 +5733,13 @@ setline({lnum}, {text})					*setline()*
 			:endfor
 <		Note: The '[ and '] marks are not set.
 
-setloclist({nr}, {list} [, {action}])			*setloclist()*
+setloclist({nr}, {list} [, {action}[, {title}]])	*setloclist()*
 		Create or replace or add to the location list for window {nr}.
 		When {nr} is zero the current window is used. For a location
 		list window, the displayed location list is modified.  For an
-		invalid window number {nr}, -1 is returned.
+		invalid window number {nr}, -1 is returned. If {title} is
+		given, it will be used to set |w:quickfix_title| after opening
+		the location window.
 		Otherwise, same as |setqflist()|.
 		Also see |location-list|.
 
@@ -5793,7 +5796,7 @@ setpos({expr}, {list})
 		|winrestview()|.
 
 
-setqflist({list} [, {action}])				*setqflist()*
+setqflist({list} [, {action}[, {title}]])		*setqflist()*
 		Create or replace or add to the quickfix list using the items
 		in {list}.  Each item in {list} is a dictionary.
 		Non-dictionary items in {list} are ignored.  Each dictionary
@@ -5832,6 +5835,9 @@ setqflist({list} [, {action}])				*setqflist()*
 		with the items from {list}. If {action} is not present or is
 		set to ' ', then a new list is created.
 
+		If {title} is given, it will be used to set |w:quickfix_title|
+		after opening the quickfix window.
+
 		Returns zero for success, -1 for failure.
 
 		This function can be used to create a quickfix list
diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index b011ee9d54..31175773f0 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -7324,10 +7324,10 @@ static struct fst {
   { "setcharsearch",     1, 1, f_setcharsearch },
   { "setcmdpos",         1, 1, f_setcmdpos },
   { "setline",           2, 2, f_setline },
-  { "setloclist",        2, 3, f_setloclist },
+  { "setloclist",        2, 4, f_setloclist },
   { "setmatches",        1, 1, f_setmatches },
   { "setpos",            2, 2, f_setpos },
-  { "setqflist",         1, 2, f_setqflist },
+  { "setqflist",         1, 3, f_setqflist },
   { "setreg",            2, 3, f_setreg },
   { "settabvar",         3, 3, f_settabvar },
   { "settabwinvar",      4, 4, f_settabwinvar },
@@ -15215,14 +15215,26 @@ static void f_setline(typval_T *argvars, typval_T *rettv)
     appended_lines_mark(lcount, added);
 }
 
-
-/*
- * Used by "setqflist()" and "setloclist()" functions
- */
-static void set_qf_ll_list(win_T *wp, typval_T *list_arg, typval_T *action_arg, typval_T *rettv)
+/// Create quickfix/location list from VimL values
+///
+/// Used by `setqflist()` and `setloclist()` functions. Accepts invalid
+/// list_arg, action_arg and title_arg arguments in which case errors out,
+/// including VAR_UNKNOWN parameters.
+///
+/// @param[in,out]  wp  Window to create location list for. May be NULL in
+///                     which case quickfix list will be created.
+/// @param[in]  list_arg  Quickfix list contents.
+/// @param[in]  action_arg  Action to perform: append to an existing list,
+///                         replace its content or create a new one.
+/// @param[in]  title_arg  New list title. Defaults to caller function name.
+/// @param[out]  rettv  Return value: 0 in case of success, -1 otherwise.
+static void set_qf_ll_list(win_T *wp, typval_T *list_arg, typval_T *action_arg,
+                           typval_T *title_arg, typval_T *rettv)
+  FUNC_ATTR_NONNULL_ARG(2, 3, 4, 5)
 {
   char_u      *act;
   int action = ' ';
+  char_u *title = NULL;
 
   rettv->vval.v_number = -1;
 
@@ -15231,7 +15243,7 @@ static void set_qf_ll_list(win_T *wp, typval_T *list_arg, typval_T *action_arg,
   else {
     list_T  *l = list_arg->vval.v_list;
 
-    if (action_arg->v_type == VAR_STRING) {
+    if (action_arg->v_type != VAR_UNKNOWN) {
       act = get_tv_string_chk(action_arg);
       if (act == NULL)
         return;                 /* type error; errmsg already given */
@@ -15239,9 +15251,20 @@ static void set_qf_ll_list(win_T *wp, typval_T *list_arg, typval_T *action_arg,
         action = *act;
     }
 
-    if (l != NULL && set_errorlist(wp, l, action,
-            (char_u *)(wp == NULL ? "setqflist()" : "setloclist()")) == OK)
+    if (title_arg->v_type != VAR_UNKNOWN) {
+      title = get_tv_string_chk(title_arg);
+      if (!title) {
+        return;  // type error; errmsg already given
+      }
+    }
+
+    if (!title) {
+      title = (char_u*)(wp ? "setloclist()" : "setqflist()");
+    }
+
+    if (l && set_errorlist(wp, l, action, title) == OK) {
       rettv->vval.v_number = 0;
+    }
   }
 }
 
@@ -15255,8 +15278,9 @@ static void f_setloclist(typval_T *argvars, typval_T *rettv)
   rettv->vval.v_number = -1;
 
   win = find_win_by_nr(&argvars[0], NULL);
-  if (win != NULL)
-    set_qf_ll_list(win, &argvars[1], &argvars[2], rettv);
+  if (win != NULL) {
+    set_qf_ll_list(win, &argvars[1], &argvars[2], &argvars[3], rettv);
+  }
 }
 
 /*
@@ -15392,7 +15416,7 @@ static void f_setpos(typval_T *argvars, typval_T *rettv)
  */
 static void f_setqflist(typval_T *argvars, typval_T *rettv)
 {
-  set_qf_ll_list(NULL, &argvars[0], &argvars[1], rettv);
+  set_qf_ll_list(NULL, &argvars[0], &argvars[1], &argvars[2], rettv);
 }
 
 /*