patch 8.1.0037: cannot easily append lines to another buffer

Problem:    Cannot easily append lines to another buffer.
Solution:   Add appendbufline().

runtime/doc/eval.txt

@@ -2560,6 +2560,21 @@ append({lnum}, {expr})					*append()*
 		0 for success.  Example: >
 			:let failed = append(line('$'), "# THE END")
 			:let failed = append(0, ["Chapter 1", "the beginning"])
+
+appendbufline({expr}, {lnum}, {text})			*appendbufline()*
+		Like |append()| but append the text in buffer {expr}.
+
+		For the use of {expr}, see |bufname()|.
+
+		{lnum} is used like with |append()|.  Note that using |line()|
+		would use the current buffer, not the one appending to.
+		Use "$" to append at the end of the buffer.
+
+		On success 0 is returned, on failure 1 is returned.
+
+		If {expr} is not a valid buffer or {lnum} is not valid, an
+		error message is given. Example: >
+			:let failed = appendbufline(13, 0, "# THE START")
 <
 							*argc()*
 argc()		The result is the number of files in the argument list of the

src/evalfunc.c

@@ -40,6 +40,7 @@ static void f_acos(typval_T *argvars, typval_T *rettv);
 static void f_add(typval_T *argvars, typval_T *rettv);
 static void f_and(typval_T *argvars, typval_T *rettv);
 static void f_append(typval_T *argvars, typval_T *rettv);
+static void f_appendbufline(typval_T *argvars, typval_T *rettv);
 static void f_argc(typval_T *argvars, typval_T *rettv);
 static void f_argidx(typval_T *argvars, typval_T *rettv);
 static void f_arglistid(typval_T *argvars, typval_T *rettv);
@@ -487,6 +488,7 @@ static struct fst
     {"add",		2, 2, f_add},
     {"and",		2, 2, f_and},
     {"append",		2, 2, f_append},
+    {"appendbufline",	3, 3, f_appendbufline},
     {"argc",		0, 0, f_argc},
     {"argidx",		0, 0, f_argidx},
     {"arglistid",	0, 2, f_arglistid},
@@ -1192,17 +1194,99 @@ f_and(typval_T *argvars, typval_T *rettv)
 }
 
 /*
- * "append(lnum, string/list)" function
+ * Get the lnum from the first argument.
+ * Also accepts "$", then "buf" is used.
+ * Returns 0 on error.
+ */
+    static linenr_T
+get_tv_lnum_buf(typval_T *argvars, buf_T *buf)
+{
+    if (argvars[0].v_type == VAR_STRING
+	    && argvars[0].vval.v_string != NULL
+	    && argvars[0].vval.v_string[0] == '$'
+	    && buf != NULL)
+	return buf->b_ml.ml_line_count;
+    return (linenr_T)get_tv_number_chk(&argvars[0], NULL);
+}
+
+/*
+ * Set line or list of lines in buffer "buf".
  */
     static void
-f_append(typval_T *argvars, typval_T *rettv)
+set_buffer_lines(
+	buf_T	    *buf,
+	linenr_T    lnum_arg,
+	int	    append,
+	typval_T    *lines,
+	typval_T    *rettv)
 {
-    long	lnum;
+    linenr_T    lnum = lnum_arg + (append ? 1 : 0);
-    char_u	*line;
+    char_u	*line = NULL;
     list_T	*l = NULL;
     listitem_T	*li = NULL;
-    typval_T	*tv;
     long	added = 0;
+    linenr_T	append_lnum;
+    buf_T	*curbuf_save = NULL;
+    win_T	*curwin_save = NULL;
+    int		is_curbuf = buf == curbuf;
+
+    /* When using the current buffer ml_mfp will be set if needed.  Useful when
+     * setline() is used on startup.  For other buffers the buffer must be
+     * loaded. */
+    if (buf == NULL || (!is_curbuf && buf->b_ml.ml_mfp == NULL) || lnum < 1)
+    {
+	rettv->vval.v_number = 1;	/* FAIL */
+	return;
+    }
+
+    if (!is_curbuf)
+    {
+	wininfo_T *wip;
+
+	curbuf_save = curbuf;
+	curwin_save = curwin;
+	curbuf = buf;
+	for (wip = buf->b_wininfo; wip != NULL; wip = wip->wi_next)
+	{
+	    if (wip->wi_win != NULL)
+	    {
+		curwin = wip->wi_win;
+		break;
+	    }
+	}
+    }
+
+    if (append)
+	// appendbufline() uses the line number below which we insert
+	append_lnum = lnum - 1;
+    else
+	// setbufline() uses the line number above which we insert, we only
+	// append if it's below the last line
+	append_lnum = curbuf->b_ml.ml_line_count;
+
+    if (lines->v_type == VAR_LIST)
+    {
+	l = lines->vval.v_list;
+	li = l->lv_first;
+    }
+    else
+	line = get_tv_string_chk(lines);
+
+    /* default result is zero == OK */
+    for (;;)
+    {
+	if (l != NULL)
+	{
+	    /* list argument, get next string */
+	    if (li == NULL)
+		break;
+	    line = get_tv_string_chk(&li->li_tv);
+	    li = li->li_next;
+	}
+
+	rettv->vval.v_number = 1;	/* FAIL */
+	if (line == NULL || lnum > curbuf->b_ml.ml_line_count + 1)
+	    break;
 
 	/* When coming here from Insert mode, sync undo, so that this can be
 	 * undone separately from what was previously inserted. */
@@ -1212,50 +1296,83 @@ f_append(typval_T *argvars, typval_T *rettv)
 	    u_sync(TRUE);
 	}
 
-    lnum = get_tv_lnum(argvars);
+	if (!append && lnum <= curbuf->b_ml.ml_line_count)
-    if (lnum >= 0
-	    && lnum <= curbuf->b_ml.ml_line_count
-	    && u_save(lnum, lnum + 1) == OK)
 	{
-	if (argvars[1].v_type == VAR_LIST)
+	    /* existing line, replace it */
+	    if (u_savesub(lnum) == OK && ml_replace(lnum, line, TRUE) == OK)
 	    {
-	    l = argvars[1].vval.v_list;
+		changed_bytes(lnum, 0);
-	    if (l == NULL)
+		if (is_curbuf && lnum == curwin->w_cursor.lnum)
-		return;
+		    check_cursor_col();
-	    li = l->lv_first;
+		rettv->vval.v_number = 0;	/* OK */
 	    }
-	for (;;)
-	{
-	    if (l == NULL)
-		tv = &argvars[1];	/* append a string */
-	    else if (li == NULL)
-		break;			/* end of list */
-	    else
-		tv = &li->li_tv;	/* append item from list */
-	    line = get_tv_string_chk(tv);
-	    if (line == NULL)		/* type error */
-	    {
-		rettv->vval.v_number = 1;	/* Failed */
-		break;
 	}
-	    ml_append(lnum + added, line, (colnr_T)0, FALSE);
+	else if (added > 0 || u_save(lnum - 1, lnum) == OK)
+	{
+	    /* append the line */
 	    ++added;
-	    if (l == NULL)
+	    if (ml_append(lnum - 1, line, (colnr_T)0, FALSE) == OK)
-		break;
+		rettv->vval.v_number = 0;	/* OK */
-	    li = li->li_next;
 	}
 
-	appended_lines_mark(lnum, added);
+	if (l == NULL)			/* only one string argument */
-	if (curwin->w_cursor.lnum > lnum)
+	    break;
-	    curwin->w_cursor.lnum += added;
+	++lnum;
+    }
+
+    if (added > 0)
+    {
+	win_T	    *wp;
+	tabpage_T   *tp;
+
+	appended_lines_mark(append_lnum, added);
+	FOR_ALL_TAB_WINDOWS(tp, wp)
+	    if (wp->w_buffer == buf && wp->w_cursor.lnum > append_lnum)
+		wp->w_cursor.lnum += added;
+	check_cursor_col();
+
 #ifdef FEAT_JOB_CHANNEL
 	if (bt_prompt(curbuf) && (State & INSERT))
 	    // show the line with the prompt
 	    update_topline();
 #endif
     }
+
+    if (!is_curbuf)
+    {
+	curbuf = curbuf_save;
+	curwin = curwin_save;
+    }
+}
+
+/*
+ * "append(lnum, string/list)" function
+ */
+    static void
+f_append(typval_T *argvars, typval_T *rettv)
+{
+    linenr_T	lnum = get_tv_lnum(&argvars[0]);
+
+    set_buffer_lines(curbuf, lnum, TRUE, &argvars[1], rettv);
+}
+
+/*
+ * "appendbufline(buf, lnum, string/list)" function
+ */
+    static void
+f_appendbufline(typval_T *argvars, typval_T *rettv)
+{
+    linenr_T	lnum;
+    buf_T	*buf;
+
+    buf = get_buf_tv(&argvars[0], FALSE);
+    if (buf == NULL)
+	rettv->vval.v_number = 1; /* FAIL */
     else
-	rettv->vval.v_number = 1;	/* Failed */
+    {
+	lnum = get_tv_lnum_buf(&argvars[1], buf);
+	set_buffer_lines(buf, lnum, TRUE, &argvars[2], rettv);
+    }
 }
 
 /*
@@ -4275,22 +4392,6 @@ get_buffer_lines(
     }
 }
 
-/*
- * Get the lnum from the first argument.
- * Also accepts "$", then "buf" is used.
- * Returns 0 on error.
- */
-    static linenr_T
-get_tv_lnum_buf(typval_T *argvars, buf_T *buf)
-{
-    if (argvars[0].v_type == VAR_STRING
-	    && argvars[0].vval.v_string != NULL
-	    && argvars[0].vval.v_string[0] == '$'
-	    && buf != NULL)
-	return buf->b_ml.ml_line_count;
-    return (linenr_T)get_tv_number_chk(&argvars[0], NULL);
-}
-
 /*
  * "getbufline()" function
  */
@@ -10225,115 +10326,6 @@ f_serverlist(typval_T *argvars UNUSED, typval_T *rettv)
     rettv->vval.v_string = r;
 }
 
-/*
- * Set line or list of lines in buffer "buf".
- */
-    static void
-set_buffer_lines(buf_T *buf, linenr_T lnum, typval_T *lines, typval_T *rettv)
-{
-    char_u	*line = NULL;
-    list_T	*l = NULL;
-    listitem_T	*li = NULL;
-    long	added = 0;
-    linenr_T	lcount;
-    buf_T	*curbuf_save = NULL;
-    win_T	*curwin_save = NULL;
-    int		is_curbuf = buf == curbuf;
-
-    /* When using the current buffer ml_mfp will be set if needed.  Useful when
-     * setline() is used on startup.  For other buffers the buffer must be
-     * loaded. */
-    if (buf == NULL || (!is_curbuf && buf->b_ml.ml_mfp == NULL) || lnum < 1)
-    {
-	rettv->vval.v_number = 1;	/* FAIL */
-	return;
-    }
-
-    if (!is_curbuf)
-    {
-	wininfo_T *wip;
-
-	curbuf_save = curbuf;
-	curwin_save = curwin;
-	curbuf = buf;
-	for (wip = buf->b_wininfo; wip != NULL; wip = wip->wi_next)
-	{
-	    if (wip->wi_win != NULL)
-	    {
-		curwin = wip->wi_win;
-		break;
-	    }
-	}
-    }
-
-    lcount = curbuf->b_ml.ml_line_count;
-
-    if (lines->v_type == VAR_LIST)
-    {
-	l = lines->vval.v_list;
-	li = l->lv_first;
-    }
-    else
-	line = get_tv_string_chk(lines);
-
-    /* default result is zero == OK */
-    for (;;)
-    {
-	if (l != NULL)
-	{
-	    /* list argument, get next string */
-	    if (li == NULL)
-		break;
-	    line = get_tv_string_chk(&li->li_tv);
-	    li = li->li_next;
-	}
-
-	rettv->vval.v_number = 1;	/* FAIL */
-	if (line == NULL || lnum > curbuf->b_ml.ml_line_count + 1)
-	    break;
-
-	/* When coming here from Insert mode, sync undo, so that this can be
-	 * undone separately from what was previously inserted. */
-	if (u_sync_once == 2)
-	{
-	    u_sync_once = 1; /* notify that u_sync() was called */
-	    u_sync(TRUE);
-	}
-
-	if (lnum <= curbuf->b_ml.ml_line_count)
-	{
-	    /* existing line, replace it */
-	    if (u_savesub(lnum) == OK && ml_replace(lnum, line, TRUE) == OK)
-	    {
-		changed_bytes(lnum, 0);
-		if (is_curbuf && lnum == curwin->w_cursor.lnum)
-		    check_cursor_col();
-		rettv->vval.v_number = 0;	/* OK */
-	    }
-	}
-	else if (added > 0 || u_save(lnum - 1, lnum) == OK)
-	{
-	    /* lnum is one past the last line, append the line */
-	    ++added;
-	    if (ml_append(lnum - 1, line, (colnr_T)0, FALSE) == OK)
-		rettv->vval.v_number = 0;	/* OK */
-	}
-
-	if (l == NULL)			/* only one string argument */
-	    break;
-	++lnum;
-    }
-
-    if (added > 0)
-	appended_lines_mark(lcount, added);
-
-    if (!is_curbuf)
-    {
-	curbuf = curbuf_save;
-	curwin = curwin_save;
-    }
-}
-
 /*
  * "setbufline()" function
  */
@@ -10351,8 +10343,7 @@ f_setbufline(argvars, rettv)
     else
     {
 	lnum = get_tv_lnum_buf(&argvars[1], buf);
-
+	set_buffer_lines(buf, lnum, FALSE, &argvars[2], rettv);
-	set_buffer_lines(buf, lnum, &argvars[2], rettv);
     }
 }
 
@@ -10512,7 +10503,7 @@ f_setline(typval_T *argvars, typval_T *rettv)
 {
     linenr_T	lnum = get_tv_lnum(&argvars[0]);
 
-    set_buffer_lines(curbuf, lnum, &argvars[1], rettv);
+    set_buffer_lines(curbuf, lnum, FALSE, &argvars[1], rettv);
 }
 
 static void set_qf_ll_list(win_T *wp, typval_T *list_arg, typval_T *action_arg, typval_T *what_arg, typval_T *rettv);

src/testdir/test_bufline.vim

@@ -1,4 +1,4 @@
-" Tests for setbufline() and getbufline()
+" Tests for setbufline(), getbufline(), appendbufline()
 
 source shared.vim
 
@@ -65,3 +65,28 @@ func Test_setline_startup()
   call delete('Xscript')
   call delete('Xtest')
 endfunc
+
+func Test_appendbufline()
+  new
+  let b = bufnr('%')
+  hide
+  call assert_equal(0, appendbufline(b, 0, ['foo', 'bar']))
+  call assert_equal(['foo'], getbufline(b, 1))
+  call assert_equal(['bar'], getbufline(b, 2))
+  call assert_equal(['foo', 'bar'], getbufline(b, 1, 2))
+  exe "bd!" b
+  call assert_equal([], getbufline(b, 1, 2))
+
+  split Xtest
+  call setline(1, ['a', 'b', 'c'])
+  let b = bufnr('%')
+  wincmd w
+  call assert_equal(1, appendbufline(b, 4, ['x']))
+  call assert_equal(1, appendbufline(1234, 1, ['x']))
+  call assert_equal(0, appendbufline(b, 3, ['d', 'e']))
+  call assert_equal(['c'], getbufline(b, 3))
+  call assert_equal(['d'], getbufline(b, 4))
+  call assert_equal(['e'], getbufline(b, 5))
+  call assert_equal([], getbufline(b, 6))
+  exe "bwipe! " . b
+endfunc

src/testdir/test_edit.vim

@@ -527,7 +527,7 @@ func! Test_edit_CTRL_I()
   " Tab in completion mode
   let path=expand("%:p:h")
   new
-  call setline(1, [path."/", ''])
+  call setline(1, [path. "/", ''])
   call feedkeys("Arunt\<c-x>\<c-f>\<tab>\<cr>\<esc>", 'tnix')
   call assert_match('runtest\.vim', getline(1))
   %d

src/version.c

@@ -761,6 +761,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    37,
 /**/
     36,
 /**/