kernel: Add support for expand after current line

9 files changed, 267 insertions, 43 deletions

diff --git a/erts/emulator/beam/break.c b/erts/emulator/beam/break.c
index dff270c60f..d7d511e982 100644
--- a/erts/emulator/beam/break.c
+++ b/erts/emulator/beam/break.c
@@ -574,6 +574,7 @@ do_break(void)
 {
     const char *helpstring = "BREAK: (a)bort (A)bort with dump (c)ontinue (p)roc info (i)nfo\n"
         "       (l)oaded (v)ersion (k)ill (D)b-tables (d)istribution\n";
+    char *clearscreen = "\E[J";
     int i;
 #ifdef __WIN32__
     char *mode; /* enough for storing "window" */
@@ -588,7 +589,14 @@ do_break(void)
 
     ASSERT(erts_thr_progress_is_blocking());
 
-    erts_printf("\n%s", helpstring);
+    /* If we are writing to something known to be a tty we clear the screen
+       after doing newline as the shell tab completion may have written
+       things there. */
+    if (!isatty(fileno(stdin)) || !isatty(fileno(stdout))) {
+        clearscreen = "";
+    }
+
+    erts_printf("\n%s%s", clearscreen, helpstring);
 
     while (1) {
 	if ((i = sys_get_key(0)) <= 0)
diff --git a/lib/kernel/src/group.erl b/lib/kernel/src/group.erl
index ae568e66ff..0fd66d29cb 100644
--- a/lib/kernel/src/group.erl
+++ b/lib/kernel/src/group.erl
@@ -47,6 +47,7 @@ server(Ancestors, Drv, Shell, Options) ->
         end,
     put(expand_fun,ExpandFun),
     put(echo, proplists:get_value(echo, Options, true)),
+    put(expand_below, proplists:get_value(expand_below, Options, true)),
 
     server_loop(Drv, start_shell(Shell), []).
 
@@ -621,7 +622,8 @@ get_line1({undefined,{_A,Mode,Char},Cs,Cont,Rs}, Drv, Shell, Ls, Encoding)
     {more_chars,Ncont,Nrs} = edlin:start(Pbs, search),
     send_drv_reqs(Drv, Nrs),
     get_line1(edlin:edit_line1(Cs, Ncont), Drv, Shell, Ls, Encoding);
-get_line1({expand, Before, Cs0, Cont,Rs}, Drv, Shell, Ls0, Encoding) ->
+get_line1({Expand, Before, Cs0, Cont,Rs}, Drv, Shell, Ls0, Encoding)
+  when Expand =:= expand; Expand =:= expand_full ->
     send_drv_reqs(Drv, Rs),
     ExpandFun = get(expand_fun),
     {Found, CompleteChars, Matches} = ExpandFun(Before, []),
@@ -633,19 +635,47 @@ get_line1({expand, Before, Cs0, Cont,Rs}, Drv, Shell, Ls0, Encoding) ->
     Cs1 = append(CompleteChars, Cs0, Encoding),
 
     MatchStr = case Matches of
-        [] -> [];
-        _ -> edlin_expand:format_matches(Matches, Width)
-    end,
+                   [] -> [];
+                   _ -> edlin_expand:format_matches(Matches, Width)
+               end,
     Cs = case {Cs1, MatchStr} of
-        {_,[]} -> Cs1;
-        {[],_} ->
-            send_drv(Drv, {put_chars, unicode, unicode:characters_to_binary("\n"++MatchStr,unicode)}),
-            [$\^L | Cs1];
-        {_,[_SingleMatch]} -> Cs1;
-        _ ->
-            send_drv(Drv, {put_chars, unicode, unicode:characters_to_binary("\n"++MatchStr,unicode)}),
-            [$\^L | Cs1]
-    end,
+             {_, []} -> Cs1;
+             {Cs1, [_SingleMatch]} when Cs1 =/= [] -> Cs1;
+             _ ->
+                 NlMatchStr = unicode:characters_to_binary("\n"++MatchStr),
+                 case get(expand_below) of
+                     true ->
+                         Lines = string:split(string:trim(MatchStr), "\n", all),
+                         NoLines = length(Lines),
+                         if NoLines > 5, Expand =:= expand ->
+                                 %% Only show 5 lines to start with
+                                 [L1,L2,L3,L4,L5|_] = Lines,
+                                 String = lists:join(
+                                            $\n,
+                                            [L1,L2,L3,L4,L5,
+                                             io_lib:format("Press tab to see all ~p expansions",
+                                                           [edlin_expand:number_matches(Matches)])]),
+                                 send_drv(Drv, {put_expand, unicode,
+                                                unicode:characters_to_binary(String)}),
+                                 Cs1;
+                            true ->
+                                 case get_tty_geometry(Drv) of
+                                     {_, Rows} when Rows > NoLines ->
+                                         %% If all lines fit on screen, we expand below
+                                         send_drv(Drv, {put_expand, unicode, NlMatchStr}),
+                                         Cs1;
+                                     _ ->
+                                         %% If there are more results than fit on
+                                         %% screen we expand above
+                                         send_drv(Drv, {put_chars, unicode, NlMatchStr}),
+                                         [$\^L | Cs1]
+                                 end
+                         end;
+                     false ->
+                         send_drv(Drv, {put_chars, unicode, NlMatchStr}),
+                         [$\^L | Cs1]
+                 end
+         end,
     get_line1(edlin:edit_line(Cs, Cont), Drv, Shell, Ls0, Encoding);
 get_line1({undefined,_Char,Cs,Cont,Rs}, Drv, Shell, Ls, Encoding) ->
     send_drv_reqs(Drv, Rs),
diff --git a/lib/kernel/src/prim_tty.erl b/lib/kernel/src/prim_tty.erl
index 6f984feba9..2b144d4b9e 100644
--- a/lib/kernel/src/prim_tty.erl
+++ b/lib/kernel/src/prim_tty.erl
@@ -138,6 +138,7 @@
                 unicode,
                 buffer_before = [],  %% Current line before cursor in reverse
                 buffer_after = [],   %% Current line after  cursor not in reverse
+                buffer_expand,       %% Characters in expand buffer
                 cols = 80,
                 rows = 24,
                 xn = false,
@@ -147,6 +148,7 @@
                 right = <<"\e[C">>,
                 %% Tab to next 8 column windows is "\e[1I", for unix "ta" termcap
                 tab = <<"\e[1I">>,
+                delete_after_cursor = <<"\e[J">>,
                 insert = false,
                 delete = false,
                 position = <<"\e[6n">>, %% "u7" on my Linux
@@ -164,6 +166,7 @@
                     }.
 -type request() ::
         {putc, unicode:unicode_binary()} |
+        {expand, unicode:unicode_binary()} |
         {insert, unicode:unicode_binary()} |
         {delete, integer()} |
         {move, integer()} |
@@ -319,6 +322,16 @@ init(State, {unix,_}) ->
                    false -> (#state{})#state.position
                end,
 
+    %% According to the manual this should only be issued when the cursor
+    %% is at position 0, but until we encounter such a console we keep things
+    %% simple and issue this with the cursor anywhere
+    DeleteAfter = case tgetstr("cd") of
+                      {ok, DA} ->
+                          DA;
+                      false ->
+                          (#state{})#state.delete_after_cursor
+                  end,
+
     State#state{
       cols = Cols,
       xn = tgetflag("xn"),
@@ -329,8 +342,9 @@ init(State, {unix,_}) ->
       insert = Insert,
       delete = Delete,
       tab = Tab,
-      position = Position
-    };
+      position = Position,
+      delete_after_cursor = DeleteAfter
+     };
 init(State, {win32, _}) ->
     State#state{
       %% position = false,
@@ -513,6 +527,26 @@ handle_request(State = #state{ options = #{ tty := false } }, Request) ->
         _Ignore ->
             {<<>>, State}
     end;
+%% Clear the expand buffer after the cursor when we handle any request.
+handle_request(State = #state{ buffer_expand = Expand, unicode = U }, Request)
+  when Expand =/= undefined ->
+    BBCols = cols(State#state.buffer_before, U),
+    BACols = cols(State#state.buffer_after, U),
+    ClearExpand = [move_cursor(State, BBCols, BBCols + BACols),
+                   State#state.delete_after_cursor,
+                   move_cursor(State, BBCols + BACols, BBCols)],
+    {Output, NewState} = handle_request(State#state{ buffer_expand = undefined }, Request),
+    {[ClearExpand, encode(Output, U)], NewState};
+%% Print characters in the expandbuffer after the cursor
+handle_request(State = #state{ unicode = U }, {expand, Binary}) ->
+    BBCols = cols(State#state.buffer_before, U),
+    BACols = cols(State#state.buffer_after, U),
+    Expand = iolist_to_binary(["\r\n",string:trim(Binary, both)]),
+    MoveToEnd = move_cursor(State, BBCols, BBCols + BACols),
+    {ExpandBuffer, NewState} = insert_buf(State#state{ buffer_expand = [] }, Expand),
+    BECols = cols(NewState#state.cols, BBCols + BACols, NewState#state.buffer_expand, U),
+    MoveToOrig = move_cursor(State, BECols, BBCols),
+    {[MoveToEnd, encode(ExpandBuffer, U), MoveToOrig], NewState};
 %% putc prints Binary and overwrites any existing characters
 handle_request(State = #state{ unicode = U }, {putc, Binary}) ->
     %% Todo should handle invalid unicode?
@@ -650,6 +684,13 @@ cols([SkipSeq | T], Unicode) when is_binary(SkipSeq) ->
     %% so we skip that
     cols(T, Unicode).
 
+cols(_ColsPerLine, CurrCols, [], _Unicode) ->
+    CurrCols;
+cols(ColsPerLine, CurrCols, ["\r\n" | T], Unicode) ->
+    CurrCols + (ColsPerLine - CurrCols) + cols(ColsPerLine, 0, T, Unicode);
+cols(ColsPerLine, CurrCols, [H | T], Unicode) ->
+    cols(ColsPerLine, CurrCols + cols([H], Unicode), T, Unicode).
+
 update_geometry(State) ->
     case tty_window_size(State#state.tty) of
         {ok, {Cols, Rows}} when Cols > 0 ->
@@ -738,6 +779,10 @@ insert_buf(State, Binary) when is_binary(Binary) ->
     insert_buf(State, Binary, [], []).
 insert_buf(State, Bin, LineAcc, Acc) ->
     case string:next_grapheme(Bin) of
+        [] when State#state.buffer_expand =/= undefined ->
+            Expand = lists:reverse(LineAcc),
+            {[Acc, characters_to_output(Expand)],
+             State#state{ buffer_expand = characters_to_buffer(Expand) }};
         [] ->
             NewBB = characters_to_buffer(LineAcc) ++ State#state.buffer_before,
             NewState = State#state{ buffer_before = NewBB },
@@ -769,12 +814,17 @@ insert_buf(State, Bin, LineAcc, Acc) ->
                    true ->
                         <<$\r>>
                 end,
-            insert_buf(State#state{ buffer_before = [], buffer_after = [] }, Rest, [],
-                       [Acc, [characters_to_output(lists:reverse(LineAcc)), Tail]]);
+            if State#state.buffer_expand =:= undefined ->
+                    insert_buf(State#state{ buffer_before = [], buffer_after = [] }, Rest, [],
+                               [Acc, [characters_to_output(lists:reverse(LineAcc)), Tail]]);
+               true ->
+                    insert_buf(State, Rest, [binary_to_list(Tail) | LineAcc], Acc)
+            end;
         [Cluster | Rest] when is_list(Cluster) ->
             insert_buf(State, Rest, [Cluster | LineAcc], Acc);
         %% We have gotten a code point that may be part of the previous grapheme cluster. 
-        [Char | Rest] when Char >= 128, LineAcc =:= [], State#state.buffer_before =/= [] ->
+        [Char | Rest] when Char >= 128, LineAcc =:= [], State#state.buffer_before =/= [],
+                           State#state.buffer_expand =:= undefined ->
             [PrevChar | BB] = State#state.buffer_before,
             case string:next_grapheme([PrevChar | Bin]) of
                 [PrevChar | _] ->
@@ -863,7 +913,7 @@ encode(UnicodeChars, false) ->
 -ifdef(debug).
 dbg(_) ->
     ok.
--endif
+-endif.
 
 %% Nif functions
 -spec isatty(stdin | stdout | stderr) -> boolean() | ebadf.
diff --git a/lib/kernel/src/user_drv.erl b/lib/kernel/src/user_drv.erl
index cf88d72a34..1a17409e6b 100644
--- a/lib/kernel/src/user_drv.erl
+++ b/lib/kernel/src/user_drv.erl
@@ -287,7 +287,7 @@ init_remote_shell(State, Node, {M, F, A}) ->
 
                     Group = group:start(self(), RShell,
                                         [{echo,State#state.shell_started =:= new}] ++
-                                            remsh_opts(RemoteNode)),
+                                            group_opts(RemoteNode)),
 
                     Gr = gr_add_cur(State#state.groups, Group, RShell),
 
@@ -311,7 +311,7 @@ init_local_shell(State, InitialShell) ->
 
     Gr = gr_add_cur(State#state.groups,
                     group:start(self(), InitialShell,
-                                [{echo,State#state.shell_started =:= new}]),
+                                group_opts() ++ [{echo,State#state.shell_started =:= new}]),
                     InitialShell),
 
     init_shell(State#state{ groups = Gr }, [Slogan,$\n]).
@@ -692,7 +692,7 @@ switch_cmd(r, Gr0) ->
     case is_alive() of
 	true ->
 	    Node = pool:get_node(),
-	    Pid = group:start(self(), {Node,shell,start,[]}, remsh_opts(Node)),
+	    Pid = group:start(self(), {Node,shell,start,[]}, group_opts(Node)),
 	    Gr = gr_add_cur(Gr0, Pid, {Node,shell,start,[]}),
 	    {retry, [], Gr};
 	false ->
@@ -703,7 +703,7 @@ switch_cmd({r, Node}, Gr) when is_atom(Node)->
 switch_cmd({r,Node,Shell}, Gr0) when is_atom(Node), is_atom(Shell) ->
     case is_alive() of
 	true ->
-            Pid = group:start(self(), {Node,Shell,start,[]}, remsh_opts(Node)),
+            Pid = group:start(self(), {Node,Shell,start,[]}, group_opts(Node)),
             Gr = gr_add_cur(Gr0, Pid, {Node,Shell,start,[]}),
             {retry, [], Gr};
         false ->
@@ -743,13 +743,17 @@ list_commands() ->
         QuitReq ++
         [{put_chars, unicode,<<"  ? | h             - this message\n">>}].
 
-remsh_opts(Node) ->
+group_opts(Node) ->
     VersionString = erpc:call(Node, erlang, system_info, [otp_release]),
     Version = list_to_integer(VersionString),
-    case Version > 25 of
-        true -> [{expand_fun,fun(B, Opts)-> erpc:call(Node,edlin_expand,expand,[B, Opts]) end}];
-        false -> [{expand_fun,fun(B, _)-> erpc:call(Node,edlin_expand,expand,[B]) end}]
-    end.
+    ExpandFun =
+        case Version > 25 of
+            true -> [{expand_fun,fun(B, Opts)-> erpc:call(Node,edlin_expand,expand,[B, Opts]) end}];
+            false -> [{expand_fun,fun(B, _)-> erpc:call(Node,edlin_expand,expand,[B]) end}]
+        end,
+    group_opts() ++ ExpandFun.
+group_opts() ->
+    [{expand_below, application:get_env(stdlib, shell_expand_location, below) =:= below}].
 
 -spec io_request(request(), prim_tty:state()) -> {noreply, prim_tty:state()} |
           {term(), reference(), prim_tty:state()}.
@@ -761,6 +765,8 @@ io_request({put_chars_sync, unicode, Chars, Reply}, TTY) ->
     {Output, NewTTY} = prim_tty:handle_request(TTY, {putc, unicode:characters_to_binary(Chars)}),
     {ok, MonitorRef} = prim_tty:write(NewTTY, Output, self()),
     {Reply, MonitorRef, NewTTY};
+io_request({put_expand, unicode, Chars}, TTY) ->
+    write(prim_tty:handle_request(TTY, {expand, unicode:characters_to_binary(Chars)}));
 io_request({move_rel, N}, TTY) ->
     write(prim_tty:handle_request(TTY, {move, N}));
 io_request({insert_chars, unicode, Chars}, TTY) ->
diff --git a/lib/kernel/test/interactive_shell_SUITE.erl b/lib/kernel/test/interactive_shell_SUITE.erl
index a87983b675..544c285412 100644
--- a/lib/kernel/test/interactive_shell_SUITE.erl
+++ b/lib/kernel/test/interactive_shell_SUITE.erl
@@ -53,6 +53,8 @@
          shell_invalid_ansi/1, shell_suspend/1, shell_full_queue/1,
          shell_unicode_wrap/1, shell_delete_unicode_wrap/1,
          shell_delete_unicode_not_at_cursor_wrap/1,
+         shell_expand_location_above/1,
+         shell_expand_location_below/1,
          shell_update_window_unicode_wrap/1,
          shell_standard_error_nlcr/1,
          remsh_basic/1, remsh_error/1, remsh_longnames/1, remsh_no_epmd/1,
@@ -126,7 +128,9 @@ groups() ->
        shell_transpose, shell_search, shell_insert,
        shell_update_window, shell_huge_input,
        shell_support_ansi_input,
-       shell_standard_error_nlcr]}
+       shell_standard_error_nlcr,
+       shell_expand_location_above,
+       shell_expand_location_below]}
     ].
 
 init_per_suite(Config) ->
@@ -872,6 +876,108 @@ shell_support_ansi_input(Config) ->
         ok
     end.
 
+shell_expand_location_below(Config) ->
+
+    Term = start_tty(Config),
+
+    {Rows, _} = get_location(Term),
+
+    NumFunctions = lists:seq(0, Rows*2),
+    FunctionName = "a_long_function_name",
+
+    Module = lists:flatten(
+               ["-module(long_module).\n",
+                "-export([",lists:join($,,[io_lib:format("~s~p/0",[FunctionName,I]) || I <- NumFunctions]),"]).\n\n",
+                [io_lib:format("~s~p() -> ok.\n",[FunctionName,I]) || I <- NumFunctions]]),
+
+    DoScan = fun F([]) ->
+                     [];
+                 F(Str) ->
+                     {done,{ok,T,_},C} = erl_scan:tokens([],Str,0),
+                     [ T | F(C) ]
+             end,
+    Forms = [ begin {ok,Y} = erl_parse:parse_form(X),Y end || X <- DoScan(Module) ],
+    {ok,_,Bin} = compile:forms(Forms, [debug_info]),
+
+    try
+        tmux(["resize-window -t ",tty_name(Term)," -x 80"]),
+
+        %% First check that basic completion works
+        send_stdin(Term, "escript:"),
+        send_stdin(Term, "\t"),
+        %% Cursor at correct place
+        check_location(Term, {-3, width("escript:")}),
+        %% Nothing after the start( completion
+        check_content(Term, "start\\($"),
+
+        %% Check that completion is cleared when we type
+        send_stdin(Term, "s"),
+        check_location(Term, {-3, width("escript:s")}),
+        check_content(Term, "escript:s$"),
+
+        %% Check that completion works when in the middle of a term
+        send_tty(Term, "Home"),
+        send_tty(Term, "["),
+        send_tty(Term, "End"),
+        send_tty(Term, ", test_after]"),
+        [send_tty(Term, "Left") || _ <- ", test_after]"],
+        send_stdin(Term, "\t"),
+        check_location(Term, {-3, width("[escript:s")}),
+        check_content(Term, "script_name\\([ ]+start\\($"),
+        send_tty(Term, "End"),
+        send_stdin(Term, ".\n"),
+
+        %% Check that we behave as we should with very long completions
+        rpc(Term, fun() ->
+                          {module, long_module} = code:load_binary(long_module, "long_module.beam", Bin)
+                  end),
+        check_content(Term, "3>"),
+        send_stdin(Term, "long_module:" ++ FunctionName),
+        send_stdin(Term, "\t"),
+        %% Check that correct text is printed below expansion
+        check_content(Term, io_lib:format("Press tab to see all ~p expansions",
+                                          [length(NumFunctions)])),
+        send_stdin(Term, "\t"),
+        %% The expansion does not fit on screen, verify that
+        %% expand above mode is used
+        check_content(fun() -> get_content(Term, "-S -5") end,
+                      "3> long_module:" ++ FunctionName ++ "\nfunctions"),
+        check_content(Term, "3> long_module:" ++ FunctionName ++ "$"),
+
+        %% We resize the terminal to make everything fit and test that
+        %% expand below mode is used
+        tmux(["resize-window -t ", tty_name(Term), " -y ", integer_to_list(Rows+10)]),
+        timer:sleep(1000), %% Sleep to make sure window has resized
+        send_stdin(Term, "\t\t"),
+        check_content(Term, "3> long_module:" ++ FunctionName ++ "\nfunctions(\n|.)*a_long_function_name99\\($"),
+        ok
+    after
+        stop_tty(Term),
+        ok
+    end.
+
+shell_expand_location_above(Config) ->
+
+    Term = start_tty([{args,["-stdlib","shell_expand_location","above"]}|Config]),
+
+    try
+        tmux(["resize-window -t ",tty_name(Term)," -x 80"]),
+        send_stdin(Term, "escript:"),
+        send_stdin(Term, "\t"),
+        check_location(Term, {0, width("escript:")}),
+        check_content(Term, "start\\(\n"),
+        check_content(Term, "escript:$"),
+        send_stdin(Term, "s"),
+        send_stdin(Term, "\t"),
+        check_location(Term, {0, width("escript:s")}),
+        check_content(Term, "\nscript_name\\([ ]+start\\(\n"),
+        check_content(Term, "escript:s$"),
+        ok
+    after
+        stop_tty(Term),
+        ok
+    end.
+
 %% Test the we can handle invalid ansi escape chars.
 %%   tmux cannot handle this... so we test this using to_erl
 shell_invalid_ansi(_Config) ->
@@ -1017,9 +1123,9 @@ shell_standard_error_nlcr(Config) ->
          try
              rpc(Term, io, format, [standard_error,"test~ntest~ntest", []]),
              check_content(Term, "test\ntest\ntest$"),
-             rpc(Term, erlang, apply, [fun() -> shell:start_interactive(),
-                                                io:format(standard_error,"test~ntest~ntest", [])
-                                       end, []]),
+             rpc(Term, fun() -> shell:start_interactive(),
+                                io:format(standard_error,"test~ntest~ntest", [])
+                       end),
              check_content(Term, "test\ntest\ntest(\n|.)*test\ntest\ntest")
          after
              stop_tty(Term)
@@ -1253,6 +1359,8 @@ tmux([Cmd|_] = Command) when is_list(Cmd) ->
 tmux(Command) ->
     string:trim(os:cmd(["tmux ",Command])).
 
+rpc(#tmux{ node = N }, Fun) ->
+    erpc:call(N, Fun).
 rpc(#tmux{ node = N }, M, F, A) ->
     erpc:call(N, M, F, A).
 
@@ -1265,7 +1373,7 @@ setup_tty(Config) ->
                                  ["-env",Key,Value]
                          end, proplists:get_value(env,Config,[])),
 
-    Args = proplists:get_value(args, Config, []),
+    ExtraArgs = proplists:get_value(args,Config,[]),
 
     ExecArgs = case os:getenv("TMUX_DEBUG") of
                    "strace" ->
@@ -1294,7 +1402,7 @@ setup_tty(Config) ->
                                   "-kernel","shell_history","disabled",
                                   "-kernel","prevent_overlapping_partitions","false",
                                   "-eval","shell:prompt_func({interactive_shell_SUITE,prompt})."
-                                 ] ++ Envs ++ Args,
+                                 ] ++ Envs ++ ExtraArgs,
                          detached => false
                        },
 
diff --git a/lib/ssh/src/ssh_cli.erl b/lib/ssh/src/ssh_cli.erl
index 43237b6141..45c1b069a9 100644
--- a/lib/ssh/src/ssh_cli.erl
+++ b/lib/ssh/src/ssh_cli.erl
@@ -670,7 +670,9 @@ start_shell(ConnectionHandler, State) ->
             {_,_,_} = Shell ->
                 Shell
         end,
-    State#state{group = group:start(self(), ShellSpawner, [{echo, get_echo(State#state.pty)}]),
+    State#state{group = group:start(self(), ShellSpawner,
+                                    [{expand_below, false},
+                                     {echo, get_echo(State#state.pty)}]),
                 buf = empty_buf()}.
 
 %%--------------------------------------------------------------------
@@ -691,7 +693,8 @@ start_exec_shell(ConnectionHandler, Cmd, State) ->
             {M,F,A} ->
                 {M, F, A++[Cmd]}
         end,
-    State#state{group = group:start(self(), ExecShellSpawner, [{echo,false}]),
+    State#state{group = group:start(self(), ExecShellSpawner, [{expand_below, false},
+                                                               {echo,false}]),
                 buf = empty_buf()}.
 
 %%--------------------------------------------------------------------
@@ -775,7 +778,8 @@ exec_in_self_group(ConnectionHandler, ChannelId, WantReply, State, Fun) ->
                           end
                   end)
         end,
-    {ok, State#state{group = group:start(self(), Exec, [{echo,false}]),
+    {ok, State#state{group = group:start(self(), Exec, [{expand_below, false},
+                                                        {echo,false}]),
                      buf = empty_buf()}}.
     
 
diff --git a/lib/stdlib/doc/src/stdlib_app.xml b/lib/stdlib/doc/src/stdlib_app.xml
index b4d0c81c96..e0f50292d6 100644
--- a/lib/stdlib/doc/src/stdlib_app.xml
+++ b/lib/stdlib/doc/src/stdlib_app.xml
@@ -57,6 +57,11 @@
         <p>Can be used to set the exception handling of the evaluator process of
           Erlang shell.</p>
       </item>
+      <tag><marker id="shell_expand_location"/><c>shell_expand_location = above | below</c></tag>
+      <item>
+          <p>Sets where the tab expansion text should appear in the shell.
+            The default is <c>below</c>.</p>
+      </item>
       <tag><marker id="shell_history_length"/><c>shell_history_length = integer() >= 0</c></tag>
       <item>
         <p>Can be used to determine how many commands are saved by the Erlang
diff --git a/lib/stdlib/src/edlin.erl b/lib/stdlib/src/edlin.erl
index 00124bd0b2..6f054d63c0 100644
--- a/lib/stdlib/src/edlin.erl
+++ b/lib/stdlib/src/edlin.erl
@@ -116,10 +116,14 @@ edit([C|Cs], P, {Bef,Aft}, Prefix, Rs0) ->
             Rs1 = erase(P, Bef, Aft, Rs0),
             Rs = redraw(P, Bef, Aft, Rs1),
             edit(Cs, P, {Bef,Aft}, none, Rs);
-        tab_expand ->
-            {expand, Bef, Cs,
-            {line, P, {Bef, Aft}, none},
-            reverse(Rs0)};
+	tab_expand ->
+	    {expand, Bef, Cs,
+	     {line, P, {Bef, Aft}, tab_expand},
+	     reverse(Rs0)};
+        tab_expand_full ->
+            {expand_full, Bef, Cs,
+	     {line, P, {Bef, Aft}, tab_expand},
+	     reverse(Rs0)};
         {undefined,C} ->
             {undefined,{none,Prefix,C},Cs,{line,P,{Bef,Aft},none},
             reverse(Rs0)};
@@ -172,6 +176,8 @@ key_map($\^E, none) -> end_of_line;
 key_map($\^F, none) -> forward_char;
 key_map($\^H, none) -> backward_delete_char;
 key_map($\t, none) -> tab_expand;
+key_map($\t, tab_expand) -> tab_expand_full;
+key_map(C, tab_expand) -> key_map(C, none);
 key_map($\^K, none) -> kill_line;
 key_map($\^L, none) -> redraw_line;
 key_map($\n, none) -> new_line;
diff --git a/lib/stdlib/src/edlin_expand.erl b/lib/stdlib/src/edlin_expand.erl
index cd386bc554..e254de11cf 100644
--- a/lib/stdlib/src/edlin_expand.erl
+++ b/lib/stdlib/src/edlin_expand.erl
@@ -22,7 +22,7 @@
 %% filepaths, variable binding, record names, function parameter values,
 %% record fields and map keys and record field values.
 -include_lib("kernel/include/eep48.hrl").
--export([expand/1, expand/2, expand/3, format_matches/2, get_exports/1,
+-export([expand/1, expand/2, expand/3, format_matches/2, number_matches/1, get_exports/1,
          shell_default_or_bif/1, bif/1, over_word/1]).
 -export([is_type/3, match_arguments1/3]).
 -record(shell_state,{
@@ -1131,6 +1131,13 @@ field_width([], W, LL) when W < LL ->
 field_width([], _, LL) ->
     LL.
 
+number_matches([#{ elems := Matches }|T]) ->
+    number_matches(Matches) + number_matches(T);
+number_matches([_|T]) ->
+    1 + number_matches(T);
+number_matches([]) ->
+    0.
+
 %% Strings are handled naively, but it should be OK here.
 longest_common_head([]) ->
     no;