updated for version 7.4.312

Problem:    Cannot figure out what argument list is being used for a window.
Solution:   Add the arglistid() function. (Marcin Szamotulski)

runtime/doc/eval.txt

@@ -1716,6 +1716,8 @@ append( {lnum}, {string})	Number	append {string} below line {lnum}
 append( {lnum}, {list})		Number	append lines {list} below line {lnum}
 argc()				Number	number of files in the argument list
 argidx()			Number	current index in the argument list
+arglistid( [{winnr}, [ {tabnr}]])
+				Number	argument list id
 argv( {nr})			String	{nr} entry of the argument list
 argv( )				List	the argument list
 asin( {expr})			Float	arc sine of {expr}
@@ -2103,6 +2105,18 @@ argc()		The result is the number of files in the argument list of the
 argidx()	The result is the current index in the argument list.  0 is
 		the first file.  argc() - 1 is the last one.  See |arglist|.
 
+							*arglistid()*
+arglistid([{winnr}, [ {tabnr} ]])
+		Return the argument list ID.  This is a number which
+		identifies the argument list being used.  Zero is used for the
+		global argument list.
+		Return zero if the arguments are invalid.
+
+		Without arguments use the current window.
+		With {winnr} only use this window in the current tab page.
+		With {winnr} and {tabnr} use the window in the specified tab
+		page.
+
 							*argv()*
 argv([{nr}])	The result is the {nr}th file in the argument list of the
 		current window.  See |arglist|.  "argv(0)" is the first one.

runtime/doc/usr_41.txt

@@ -772,6 +772,7 @@ Date and Time:				*date-functions* *time-functions*
 Buffers, windows and the argument list:
 	argc()			number of entries in the argument list
 	argidx()		current position in the argument list
+	arglistid()		get id of the argument list
 	argv()			get one entry from the argument list
 	bufexists()		check if a buffer exists
 	buflisted()		check if a buffer exists and is listed

src/eval.c

@@ -463,6 +463,7 @@ static void f_and __ARGS((typval_T *argvars, typval_T *rettv));
 static void f_append __ARGS((typval_T *argvars, typval_T *rettv));
 static void f_argc __ARGS((typval_T *argvars, typval_T *rettv));
 static void f_argidx __ARGS((typval_T *argvars, typval_T *rettv));
+static void f_arglistid __ARGS((typval_T *argvars, typval_T *rettv));
 static void f_argv __ARGS((typval_T *argvars, typval_T *rettv));
 #ifdef FEAT_FLOAT
 static void f_asin __ARGS((typval_T *argvars, typval_T *rettv));
@@ -7875,6 +7876,7 @@ static struct fst
     {"append",		2, 2, f_append},
     {"argc",		0, 0, f_argc},
     {"argidx",		0, 0, f_argidx},
+    {"arglistid",	0, 2, f_arglistid},
     {"argv",		0, 1, f_argv},
 #ifdef FEAT_FLOAT
     {"asin",		1, 1, f_asin},	/* WJMc */
@@ -8858,6 +8860,41 @@ f_argidx(argvars, rettv)
     rettv->vval.v_number = curwin->w_arg_idx;
 }
 
+/*
+ * "arglistid()" function
+ */
+    static void
+f_arglistid(argvars, rettv)
+    typval_T	*argvars UNUSED;
+    typval_T	*rettv;
+{
+    win_T	*wp;
+    tabpage_T	*tp = NULL;
+    long	n;
+
+    rettv->vval.v_number = -1;
+    if (argvars[0].v_type != VAR_UNKNOWN)
+    {
+	if (argvars[1].v_type != VAR_UNKNOWN)
+	{
+	    n = get_tv_number(&argvars[1]);
+	    if (n >= 0)
+		tp = find_tabpage(n);
+	}
+	else
+	    tp = curtab;
+
+	if (tp != NULL)
+	{
+	    wp = find_win_by_nr(&argvars[0], tp);
+	    if (wp != NULL)
+		rettv->vval.v_number = wp->w_alist->id;
+	}
+    }
+    else
+	rettv->vval.v_number = curwin->w_alist->id;
+}
+
 /*
  * "argv(nr)" function
  */

src/ex_docmd.c

@@ -7211,6 +7211,7 @@ alist_new()
     else
     {
 	curwin->w_alist->al_refcount = 1;
+	curwin->w_alist->id = ++max_alist_id;
 	alist_init(curwin->w_alist);
     }
 }

src/globals.h

@@ -601,6 +601,7 @@ EXTERN int	mf_dont_release INIT(= FALSE);	/* don't release blocks */
  * to this when the window is using the global argument list.
  */
 EXTERN alist_T	global_alist;	/* global argument list */
+EXTERN int	max_alist_id INIT(= 0);	    /* the previous argument list id */
 EXTERN int	arg_had_last INIT(= FALSE); /* accessed last file in
 					       global_alist */
 

src/main.c

@@ -322,6 +322,7 @@ main
     init_yank();		/* init yank buffers */
 
     alist_init(&global_alist);	/* Init the argument list to empty. */
+    global_alist.id = 0;
 
     /*
      * Set the default values for the options.

src/structs.h

@@ -675,6 +675,7 @@ typedef struct arglist
 {
     garray_T	al_ga;		/* growarray with the array of file names */
     int		al_refcount;	/* number of windows using this arglist */
+    int		id;		/* id of this arglist */
 } alist_T;
 
 /*

src/version.c

@@ -734,6 +734,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    312,
 /**/
     311,
 /**/