Add test suite for the tools application

1 files changed, 815 insertions, 0 deletions

diff --git a/lib/tools/test/eprof_SUITE_data/eed.erl b/lib/tools/test/eprof_SUITE_data/eed.erl
new file mode 100644
index 0000000000..0175abdd0e
--- /dev/null
+++ b/lib/tools/test/eprof_SUITE_data/eed.erl
@@ -0,0 +1,815 @@
+%%%----------------------------------------------------------------------
+%%% File    : eed.erl
+%%% Author  : Bjorn Gustavsson <bjorn@strider>
+%%% Purpose : Unix `ed' look-alike.
+%%% Created : 24 Aug 1997 by Bjorn Gustavsson <bjorn@strider>
+%%%----------------------------------------------------------------------
+
+-module(eed).
+-author('bjorn@strider').
+
+-export([edit/0, edit/1, file/1, cmd_line/1]).
+
+-record(state, {dot = 0,			% Line number of dot.
+		upto_dot = [],			% Lines up to dot (reversed).
+		after_dot = [],			% Lines after dot.
+		lines = 0,			% Total number of lines.
+		print=false,			% Print after command.
+		filename=[],			% Current file.
+		pattern,			% Current pattern.
+		in_global=false,		% True if executing global command.
+		input=[],			% Global input stream.
+		undo,				% Last undo state.
+		marks=[],			% List of marks.
+		modified=false,			% Buffer is modified.
+		opts=[{prompt, ''}],		% Options.
+		last_error,			% The last error encountered.
+		input_fd			% Input file descriptor.
+	       }).
+
+-record(line, {contents,			% Contents of line.
+	       mark=false			% Marked (for global prefix).
+	      }).
+
+cmd_line([Script]) ->
+    file(Script),
+    halt().
+
+file(Script) ->
+    case file:open(Script, [read]) of
+	{ok,Fd} ->
+	    loop(#state{input_fd=Fd}),
+	    ok;
+	{error,E} ->
+	    {error,E}
+    end.
+
+edit() ->
+    loop(#state{input_fd=group_leader()}).
+
+edit(Name) ->
+    loop(command([$e|Name], #state{input_fd=group_leader()})).
+
+loop(St0) ->
+    {ok, St1, Cmd} = get_line(St0),
+    case catch command(lib:nonl(Cmd), St1) of
+	{'EXIT', Reason} ->
+	    %% XXX Should clear outstanding global command here.
+	    loop(print_error({'EXIT', Reason}, St1));
+	quit ->
+	    ok;
+	{error, Reason} ->
+	    loop(print_error(Reason, St1));
+	St2 when record(St2, state) ->
+	    loop(St2)
+    end.
+
+command(Cmd, St) ->
+    case parse_command(Cmd, St) of
+	quit ->
+	    quit;
+	St1 when function(St1#state.print) ->
+	    if
+		St1#state.dot /= 0 ->
+		    print_current(St1);
+		true ->
+		    ok
+	    end,
+	    St1#state{print=false};
+	St1 when record(St1, state) ->
+	    St1
+    end.
+
+get_line(St) ->
+    Opts = St#state.opts,
+    {value, {prompt, Prompt}} = lists:keysearch(prompt, 1, Opts),
+    get_line(Prompt, St).
+
+get_line(Prompt, St) when St#state.input == [] ->
+    Line = get_line1(St#state.input_fd, Prompt, []),
+    {ok, St, Line};
+get_line(_, St) ->
+    get_input(St#state.input, St, []).
+
+get_input([eof], St, []) ->
+    {ok, St, eof};
+get_input([eof], St, Result) ->
+    {ok, St#state{input=[eof]}, lists:reverse(Result)};
+get_input([$\n|Rest], St, Result) ->
+    {ok, St#state{input=Rest}, lists:reverse(Result)};
+get_input([C|Rest], St, Result) ->
+    get_input(Rest, St, [C|Result]).
+
+get_line1(Io, Prompt, Result) ->
+    get_line2(Io, io:get_line(Io, Prompt), Result).
+
+get_line2(Io, eof, []) ->
+    eof;
+get_line2(Io, eof, Result) ->
+    lists:reverse(Result);
+get_line2(Io, [$\\, $\n], Result) ->
+    get_line1(Io, '', [$\n|Result]);
+get_line2(Io, [$\n], Result) ->
+    lists:reverse(Result, [$\n]);
+get_line2(Io, [C|Rest], Result) ->
+    get_line2(Io, Rest, [C|Result]).
+
+print_error(Reason, St0) ->
+    St1 = St0#state{last_error=Reason},
+    io:put_chars("?\n"),
+    case lists:member(help_always, St1#state.opts) of
+	true ->
+	    help_command([], [], St1),
+	    St1;
+	false ->
+	    St1
+    end.
+
+format_error(bad_command) -> "unknown command";
+format_error(bad_filename) -> "illegal or missing filename";
+format_error(bad_file) -> "cannot open input file";
+format_error(bad_linenum) -> "line out of range";
+format_error(bad_delimiter) -> "illegal or missing delimiter";
+format_error(bad_undo) -> "nothing to undo";
+format_error(bad_mark) -> "mark not lower case ascii";
+format_error(bad_pattern) -> "invalid regular expression";
+format_error(buffer_modified) -> "warning: expecting `w'";
+format_error(nested_globals) -> "multiple globals not allowed";
+format_error(nomatch) -> "search string not found";
+format_error(missing_space) -> "no space after command";
+format_error(garbage_after_command) -> "illegal suffix";
+format_error(not_implemented) -> "not implemented yet";
+format_error({'EXIT', {Code, {Mod, Func, Args}}}) ->
+    lists:flatten(io_lib:format("aborted due to bug (~p)",
+				[{Code, {Mod, Func, length(Args)}}]));
+format_error(A) -> atom_to_list(A).
+
+
+
+%%% Parsing commands.
+
+parse_command(Cmd, St) ->
+    parse_command(Cmd, St, []).
+
+parse_command(Cmd, State, Nums) ->
+    case get_one(Cmd, State) of
+	{ok, Num, Rest, NewState} ->
+	    parse_next_address(Rest, NewState, [Num|Nums]);
+	false ->
+	    parse_command1(Cmd, State, Nums)
+    end.
+
+parse_next_address([$,|Rest], State, Nums) ->
+    parse_command(Rest, State, Nums);
+parse_next_address([$;|Rest], State, [Num|Nums]) ->
+    parse_command(Rest, move_to(Num, State), [Num|Nums]);
+parse_next_address(Rest, State, Nums) ->
+    parse_command1(Rest, State, Nums).
+
+parse_command1([Letter|Rest], State, Nums) ->
+    Cont = fun(Fun, NumLines, Def) ->
+		   execute_command(Fun, NumLines, Def, State, Nums, Rest) end,
+    parse_cmd_char(Letter, Cont);
+parse_command1([], State, Nums) ->
+    execute_command(fun print_command/3, 1, next, State, Nums, []).
+
+get_one(Cmd, St) ->
+    case get_address(Cmd, St) of
+	{ok, Addr, Cmd1, St1} ->
+	    get_one1(Cmd1, Addr, St1);
+	false ->
+	    get_one1(Cmd, false, St)
+    end.
+
+get_one1([D|Rest], false, St) when $0 =< D, D =< $9 ->
+    get_one2(get_number([D|Rest]), 1, 0, St);
+get_one1([D|Rest], Sum, St) when $0 =< D, D =< $9 ->
+    get_one2(get_number([D|Rest]), 1, Sum, St);
+get_one1([$+, D|Rest], Sum, St) when $0 =< D, D =< $9 ->
+    get_one2(get_number([D|Rest]), 1, Sum, St);
+get_one1([$-, D|Rest], Sum, St) when $0 =< D, D =< $9 ->
+    get_one2(get_number([D|Rest]), -1, Sum, St);
+get_one1([$+|Rest], Sum, St) ->
+    get_one2({ok, 1, Rest}, 1, Sum, St);
+get_one1([$-|Rest], Sum, St) ->
+    get_one2({ok, 1, Rest}, -1, Sum, St);
+get_one1(Cmd, false, St) ->
+    false;
+get_one1(Cmd, Sum, St) ->
+    {ok, Sum, Cmd, St}.
+
+get_one2({ok, Number, Rest}, Mul, false, St) ->
+    get_one1(Rest, St#state.dot+Mul*Number, St);
+get_one2({ok, Number, Rest}, Mul, Sum, St) ->
+    get_one1(Rest, Sum+Mul*Number, St).
+
+get_number(Cmd) ->
+    get_number(Cmd, 0).
+
+get_number([D|Rest], Result) when $0 =< D, D =< $9 ->
+    get_number(Rest, Result*10+D-$0);
+get_number(Rest, Result) ->
+    {ok, Result, Rest}.
+
+get_address([$.|Rest], State) ->
+    {ok, State#state.dot, Rest, State};
+get_address([$$|Rest], State) ->
+    {ok, State#state.lines, Rest, State};
+get_address([$', Mark|Rest], St) when $a =< Mark, Mark =< $z ->
+    case lists:keysearch(Mark, 2, St#state.marks) of
+	{value, {Line, Mark}} ->
+	    {ok, Line, Rest, St};
+	false ->
+	    {ok, 0, Rest, St}
+    end;
+get_address([$'|Rest], State) ->
+    error(bad_mark);
+get_address([$/|Rest], State) ->
+    scan_forward($/, Rest, State);
+get_address([$?|Rest], State) ->
+    error(not_implemented);
+get_address(Cmd, St) ->
+    false.
+
+scan_forward(End, Patt0, State) ->
+    {ok, Rest, NewState} = get_pattern(End, Patt0, State),
+    Dot = NewState#state.dot,
+    After = NewState#state.after_dot,
+    scan_forward1(Dot+1, After, NewState, Rest).
+
+scan_forward1(Linenum, [Line|Rest], State, RestCmd) ->
+    case regexp:first_match(Line#line.contents, State#state.pattern) of
+	{match, _, _} ->
+	    {ok, Linenum, RestCmd, State};
+	nomatch ->
+	    scan_forward1(Linenum+1, Rest, State, RestCmd)
+    end;
+scan_forward1(_, [], State, RestCmd) ->
+    Dot = State#state.dot,
+    Upto = State#state.upto_dot,
+    case scan_forward2(Dot, Upto, State, RestCmd) of
+	false ->
+	    error(bad_linenum);
+	Other ->
+	    Other
+    end.
+
+scan_forward2(0, [], State, RestCmd) ->
+    false;
+scan_forward2(Linenum, [Line|Rest], State, RestCmd) ->
+    case scan_forward2(Linenum-1, Rest, State, RestCmd) of
+	false ->
+	    case regexp:first_match(Line#line.contents, State#state.pattern) of
+		{match, _, _} ->
+		    {ok, Linenum, RestCmd, State};
+		nomatch ->
+		    false
+	    end;
+	Other ->
+	    Other
+    end.
+
+parse_cmd_char($S, Cont) -> Cont(fun quest_command/3, 0, none);
+parse_cmd_char($T, Cont) -> Cont(fun time_command/3, 0, none);
+parse_cmd_char($=, Cont) -> Cont(fun print_linenum/3, 1, last);
+parse_cmd_char($a, Cont) -> Cont(fun append_command/3, 1, dot);
+parse_cmd_char($c, Cont) -> Cont(fun change_command/3, 2, dot);
+parse_cmd_char($d, Cont) -> Cont(fun delete_command/3, 2, dot);
+parse_cmd_char($e, Cont) -> Cont(fun enter_command/3, 0, none);
+parse_cmd_char($E, Cont) -> Cont(fun enter_always_command/3, 0, none);
+parse_cmd_char($f, Cont) -> Cont(fun file_command/3, 0, none);
+parse_cmd_char($g, Cont) -> Cont(fun global_command/3, 2, all);
+parse_cmd_char($h, Cont) -> Cont(fun help_command/3, 0, none);
+parse_cmd_char($H, Cont) -> Cont(fun help_always_command/3, 0, none);
+parse_cmd_char($i, Cont) -> Cont(fun insert_command/3, 1, dot);
+parse_cmd_char($k, Cont) -> Cont(fun mark_command/3, 1, dot);
+parse_cmd_char($l, Cont) -> Cont(fun list_command/3, 2, dot);
+parse_cmd_char($m, Cont) -> Cont(fun move_command/3, 2, dot);
+parse_cmd_char($n, Cont) -> Cont(fun number_command/3, 2, dot);
+parse_cmd_char($p, Cont) -> Cont(fun print_command/3, 2, dot);
+parse_cmd_char($P, Cont) -> Cont(fun prompt_command/3, 0, none);
+parse_cmd_char($q, Cont) -> Cont(fun quit_command/3, 0, none);
+parse_cmd_char($Q, Cont) -> Cont(fun quit_always_command/3, 0, none);
+parse_cmd_char($r, Cont) -> Cont(fun read_command/3, 1, last);
+parse_cmd_char($s, Cont) -> Cont(fun subst_command/3, 2, dot);
+parse_cmd_char($t, Cont) -> Cont(fun transpose_command/3, 2, dot);
+parse_cmd_char($u, Cont) -> Cont(fun undo_command/3, 0, none);
+parse_cmd_char($v, Cont) -> Cont(fun vglobal_command/3, 2, all);
+parse_cmd_char($w, Cont) -> Cont(fun write_command/3, 2, all);
+parse_cmd_char(_, Cont)  -> error(bad_command).
+
+execute_command(Fun, NumLines, Def, State, Nums, Rest) ->
+    Lines = check_lines(NumLines, Def, Nums, State),
+    Fun(Rest, Lines, State).
+
+check_lines(0, _, [], _State) ->
+    [];
+check_lines(1, dot, [], #state{dot=Dot}) ->
+    [Dot];
+check_lines(1, next, [], State) when State#state.dot < State#state.lines ->
+    [State#state.dot+1];
+check_lines(1, last, [], State) ->
+    [State#state.lines];
+check_lines(1, _, [Num|_], State) when 0 =< Num, Num =< State#state.lines ->
+    [Num];
+check_lines(2, dot, [], #state{dot=Dot}) ->
+    [Dot, Dot];
+check_lines(2, all, [], #state{lines=Lines}) ->
+    [1, Lines];
+check_lines(2, _, [Num], State) when 0 =< Num, Num =< State#state.lines ->
+    [Num, Num];
+check_lines(2, _, [Num2, Num1|_], State)
+when 0 =< Num1, Num1 =< Num2, Num2 =< State#state.lines ->
+    [Num1, Num2];
+check_lines(_, _, _, _) ->
+    error(bad_linenum).
+
+
+%%% Executing commands.
+
+%% ($)= - print line number
+
+print_linenum(Rest, [Line], State) ->
+    NewState = check_trailing_p(Rest, State),
+    io:format("~w\n", [Line]),
+    NewState.
+
+%% ? - print state (for debugging)
+
+quest_command([], [], State) ->
+    io:format("~p\n", [State]),
+    State.
+
+%% Tcmd - time command
+
+time_command(Cmd, [], St) ->
+    Fun = fun parse_command/2,
+    erlang:garbage_collect(),
+    {Elapsed, Val} = timer:tc(erlang, apply, [Fun, [Cmd, St]]),
+    io:format("Time used: ~p s~n", [Elapsed/1000000.0]),
+    case Val of
+	{error, Reason} ->
+	    throw({error, Reason});
+	Other ->
+	    Other
+    end.
+
+%% (.)a - append text
+
+append_command(Rest, [Line], St0) ->
+    St1 = save_for_undo(St0),
+    append(move_to(Line, check_trailing_p(Rest, St1))).
+
+append(St0) ->
+    {ok, St1, Line0} = get_line('', St0),
+    case Line0 of
+	eof ->
+	    St1;
+	".\n" ->
+	    St1;
+	Line ->
+	    append(insert_line(Line, St1))
+    end.
+
+%% (.,.)c
+
+change_command(Rest, Lines, St0) ->
+    St1 = delete_command(Rest, Lines, St0),
+    St2 = append_command([], [St1#state.dot-1], St1),
+    save_for_undo(St2, St0).
+
+%% (.,.)d - delete lines
+
+delete_command(Rest, [0, Last], St) ->
+    error(bad_linenum);
+delete_command(Rest, [First, Last], St0) ->
+    St1 = check_trailing_p(Rest, save_for_undo(St0)),
+    delete(Last-First+1, move_to(Last, St1)).
+
+delete(0, St) when St#state.dot == St#state.lines ->
+    St;
+delete(0, St) ->
+    next_line(St);
+delete(Left, St0) ->
+    St1 = delete_current_line(St0),
+    delete(Left-1, St1).
+
+%% e file - replace buffer with new file
+
+enter_command(Name, [], St) when St#state.modified == true ->
+    error(buffer_modified);
+enter_command(Name, [], St0) ->
+    enter_always_command(Name, [], St0).
+
+%% E file - replace buffer with new file
+
+enter_always_command(Name, [], St0) ->
+    St1 = read_command(Name, [0], #state{filename=St0#state.filename,
+					 opts=St0#state.opts}),
+    St1#state{modified=false}.
+
+%% f file - print filename; set filename
+
+file_command([], [], St) ->
+    io:format("~s~n", [St#state.filename]),
+    St;
+file_command([$_|Name0], [], St) ->
+    Name = skip_blanks(Name0),
+    file_command([], [], St#state{filename=Name});
+file_command(_, _, _) ->
+    error(missing_space).
+
+%% (1,$)g/RE/commands - execute commands on all matching lines.
+%% (1,$)v/RE/commands - execute commands on all non-matching lines.
+
+global_command(Cmd, Lines, St) ->
+    check_global0(true, Cmd, Lines, St).
+
+vglobal_command(Cmd, Lines, St) ->
+    check_global0(false, Cmd, Lines, St).
+
+check_global0(_, _, _, St) when St#state.in_global == true ->
+    error(nested_globals);
+check_global0(Sense, [Sep|Pattern], Lines, St0) ->
+    {ok, Cmd, St1} = get_pattern(Sep, Pattern, St0),
+    St2 = mark(Sense, Lines, St1),
+    do_global_command(Cmd, St2#state{in_global=true}, 0).
+    
+mark(Sense, [First, Last], St0) ->
+    St1 = move_to(Last, St0),
+    mark1(Sense, First-1, St1).
+
+mark1(Sense, First, St) when St#state.dot == First ->
+    St;
+mark1(Sense, First, St) ->
+    [Line|Prev] = St#state.upto_dot,
+    NewLine = case match(St) of
+		  true  -> Line#line{mark=Sense};
+		  false -> Line#line{mark=not(Sense)}
+	      end,
+    mark1(Sense, First, prev_line(St#state{upto_dot=[NewLine|Prev]})).
+
+do_global_command(Cmd, St0, Matches) ->
+    case find_mark(St0) of
+	{ok, St1} ->
+	    St2 = St1#state{input=Cmd++[eof]},
+	    {ok, St3, Cmd1} = get_line(St2),
+	    St4 = command(Cmd1, St3),
+	    %% XXX There might be several commands.
+	    do_global_command(Cmd, St4, Matches+1);
+	false when Matches == 0 ->
+	    error(nomatch);
+	false ->
+	    St0#state{in_global=false, input=[]}
+    end.
+
+find_mark(State) ->
+    find_mark(State#state.lines, State).
+
+find_mark(0, _State) ->
+    false;
+find_mark(Limit, State) when State#state.dot == 0 ->
+    find_mark(Limit, next_line(State));
+find_mark(Limit, State) ->
+    case State#state.upto_dot of
+	[Line|Prev] when Line#line.mark == true ->
+	    NewLine = Line#line{mark=false},
+	    {ok, State#state{upto_dot=[NewLine|Prev]}};
+	_Other ->
+	    find_mark(Limit-1, wrap_next_line(State))
+    end.
+
+%% h - print info about last error
+
+help_command([], [], St) ->
+    case St#state.last_error of
+	undefined ->
+	    St;
+	Reason ->
+	    io:put_chars(format_error(Reason)),
+	    io:nl(),
+	    St
+    end;
+help_command(_, _, _) ->
+    error(garbage_after_command).
+
+%% H - toggle automatic help mode on/off
+
+help_always_command([], [], St) ->
+    Opts = St#state.opts,
+    case lists:member(help_always, Opts) of
+	true ->
+	    St#state{opts=Opts--[help_always]};
+	false ->
+	    help_command([], [], St),
+	    St#state{opts=[help_always|Opts]}
+    end.
+
+%% (.)i - insert text
+
+insert_command(Rest, [0], State) ->
+    error(bad_linenum);
+insert_command(Rest, [Line], State) ->
+    append_command(Rest, [Line-1], State).
+
+%% (.)kx - mark line
+
+mark_command(_, [0], St) ->
+    error(bad_linenum);
+mark_command([Mark|Rest], [Line], St) when $a =< Mark, Mark =< $z ->
+    error(not_implemented);
+mark_command(_, _, _) ->
+    error(bad_mark).
+    
+%% (.,.)l - list lines
+
+list_command(Rest, Lines, St) ->
+    print([$l|Rest], Lines, St).
+
+%% (.,.)m - move lines
+
+move_command(Cmd, [First, Last], St) ->
+    error(not_implemented).
+
+%% (.,.)t - copy lines
+
+transpose_command(Cmd, [First, Last], St) ->
+    error(not_implemented).
+
+%% (.,.)n - print lines with line numbers
+
+number_command(Rest, Lines, St) ->
+    print([$n|Rest], Lines, St).
+
+%% (.,.)p - print lines
+
+print_command(Rest, Lines, St) ->
+    print([$p|Rest], Lines, St).
+
+%% P - toggle prompt
+
+prompt_command([], [], St) ->
+    Opts = St#state.opts,
+    case lists:keysearch(prompt, 1, Opts) of
+	{value, {prompt, ''}} ->
+	    St#state{opts=[{prompt, '*'}|Opts]};
+	{value, Value} ->
+	    St#state{opts=[{prompt, ''} | Opts--[Value]]}
+    end;
+prompt_command(_, _, _) ->
+    error(garbage_after_command).
+
+%% q - quit editor
+
+quit_command([], [], _) ->
+    quit;
+quit_command(_, _, _) ->
+    error(garbage_after_command).
+
+%% Q - quit editor
+
+quit_always_command([], [], _) ->
+    quit;
+quit_always_command(_, _, _) ->
+    error(garbage_after_command).
+
+%% ($)r file - read file
+
+read_command([], _, St) when St#state.filename == [] ->
+    error(bad_filename);
+read_command([], [After], St) ->
+    read(After, St#state.filename, St);
+read_command([$ |Name0], [After], St) when St#state.filename == [] ->
+    Name = skip_blanks(Name0),
+    read(After, Name, St#state{filename=Name});
+read_command([$ |Name0], [After], St) ->
+    Name = skip_blanks(Name0),
+    read(After, Name, St);
+read_command(_, _, _) ->
+    error(missing_space).
+
+read(After, Name, St0) ->
+    case file:read_file(Name) of
+	{ok, Bin} ->
+	    Chars = size(Bin),
+	    St1 = move_to(After, St0),
+	    St2 = insert_line(binary_to_list(Bin), St1),
+	    io:format("~w~n", [Chars]),
+	    St2;
+	{error, _} ->
+	    error(bad_file)
+    end.
+
+%% s/pattern/replacement/gp
+
+subst_command(_, [0, _], _) ->
+    error(bad_linenum);
+subst_command([$ |Cmd0], [First, Last], St0) ->
+    error(bad_delimiter);
+subst_command([$\n|Cmd0], [First, Last], St0) ->
+    error(bad_delimiter);
+subst_command([Sep|Cmd0], [First, Last], St0) ->
+    St1 = save_for_undo(St0),
+    {ok, Cmd1, St2} = get_pattern(Sep, Cmd0, St1),
+    {ok, Replacement, Cmd2} = get_replacement(Sep, Cmd1),
+    {ok, Sub, Cmd3} = subst_check_gflag(Cmd2),
+    St3 = check_trailing_p(Cmd3, St2),
+    subst_command(Last-First+1, Sub, Replacement, move_to(First-1, St3), nomatch);
+subst_command([], _, _) ->
+    error(bad_delimiter).
+    
+subst_command(0, _, _, _, nomatch) ->
+    error(nomatch);
+subst_command(0, _, _, _, StLast) when record(StLast, state) ->
+    StLast;
+subst_command(Left, Sub, Repl, St0, LastMatch) ->
+    St1 = next_line(St0),
+    [Line|_] = St1#state.upto_dot,
+    case regexp:Sub(Line#line.contents, St1#state.pattern, Repl) of
+	{ok, _, 0} ->
+	    subst_command(Left-1, Sub, Repl, St1, LastMatch);
+	{ok, NewContents, _} ->
+	    %% XXX This doesn't work with marks.
+	    St2 = delete_current_line(St1),
+	    St3 = insert_line(NewContents, St2),
+	    subst_command(Left-1, Sub, Repl, St3, St3)
+    end.
+
+subst_check_gflag([$g|Cmd]) -> {ok, gsub, Cmd};
+subst_check_gflag(Cmd)      -> {ok, sub, Cmd}.
+
+%% u - undo
+
+undo_command([], [], St) when St#state.undo == undefined ->
+    error(bad_undo);
+undo_command([], [], #state{undo=Undo}) ->
+    Undo;
+undo_command(_, _, _) ->
+    error(garbage_after_command).
+
+%% (1,$)w - write buffer to file
+
+write_command(Cmd, [First, Last], St) ->
+    error(not_implemented).
+    
+
+%%% Primitive buffer operations.
+
+print_current(St) ->
+    [Line|_] = St#state.upto_dot,
+    Printer = St#state.print,
+    Printer(Line#line.contents, St).
+
+delete_current_line(St) when St#state.dot == 0 ->
+    error(bad_linenum);
+delete_current_line(St) ->
+    Lines = St#state.lines,
+    [_|Prev] = St#state.upto_dot,
+    St#state{dot=St#state.dot-1, upto_dot=Prev, lines=Lines-1, modified=true}.
+    
+insert_line(Line, State) ->
+    insert_line1(Line, State, []).
+
+insert_line1([$\n|Rest], State, Result) ->
+    NewState = insert_single_line(lists:reverse(Result, [$\n]), State),
+    insert_line1(Rest, NewState, []);
+insert_line1([C|Rest], State, Result) ->
+    insert_line1(Rest, State, [C|Result]);
+insert_line1([], State, []) ->
+    State;
+insert_line1([], State, Result) ->
+    insert_single_line(lists:reverse(Result, [$\n]), State).
+
+insert_single_line(Line0, State) ->
+    Line = #line{contents=Line0},
+    Dot = State#state.dot,
+    Before = State#state.upto_dot,
+    Lines = State#state.lines,
+    %% XXX Avoid updating the record every time.
+    State#state{dot=Dot+1, upto_dot=[Line|Before], lines=Lines+1, modified=true}.
+
+move_to(Line, State) when Line < State#state.dot ->
+    move_to(Line, prev_line(State));
+move_to(Line, State) when State#state.dot < Line ->
+    move_to(Line, next_line(State));
+move_to(Line, State) when Line == State#state.dot ->
+    State.
+
+prev_line(State) ->
+    Dot = State#state.dot,
+    Before = State#state.upto_dot,
+    After = State#state.after_dot,
+    State#state{dot=Dot-1, upto_dot=tl(Before), after_dot=[hd(Before)|After]}.
+
+next_line(State) ->
+    Dot = State#state.dot,
+    Before = State#state.upto_dot,
+    After = State#state.after_dot,
+    State#state{dot=Dot+1, upto_dot=[hd(After)|Before], after_dot=tl(After)}.
+
+wrap_next_line(State) when State#state.dot == State#state.lines ->
+    move_to(1, State);
+wrap_next_line(State) ->
+    next_line(State).
+
+
+%%% Utilities.
+
+get_pattern(End, Cmd, State) ->
+    get_pattern(End, Cmd, State, []).
+
+get_pattern(End, [End|Rest], State, []) when State#state.pattern /= undefined ->
+    {ok, Rest, State};
+get_pattern(End, [End|Rest], State, Result) ->
+    case regexp:parse(lists:reverse(Result)) of
+	{error, _} ->
+	    error(bad_pattern);
+	{ok, Re} ->
+	    {ok, Rest, State#state{pattern=Re}}
+    end;
+get_pattern(End, [C|Rest], State, Result) ->
+    get_pattern(End, Rest, State, [C|Result]);
+get_pattern(End, [], State, Result) ->
+    get_pattern(End, [End], State, Result).
+
+get_replacement(End, Cmd) ->
+    get_replacement(End, Cmd, []).
+
+get_replacement(End, [End|Rest], Result) ->
+    {ok, lists:reverse(Result), Rest};
+get_replacement(End, [$\\, $&|Rest], Result) ->
+    get_replacement(End, Rest, [$&, $\\|Result]);
+get_replacement(End, [$\\, C|Rest], Result) ->
+    get_replacement(End, Rest, [C|Result]);
+get_replacement(End, [C|Rest], Result) ->
+    get_replacement(End, Rest, [C|Result]);
+get_replacement(End, [], Result) ->
+    get_replacement(End, [End], Result).
+
+check_trailing_p([$l], St) ->
+    St#state{print=fun(Line, _) -> lister(Line, 0) end};
+check_trailing_p([$n], St) ->
+    St#state{print=fun numberer/2};
+check_trailing_p([$p], St) ->
+    St#state{print=fun(Line, _) -> io:put_chars(Line) end};
+check_trailing_p([], State) ->
+    State;
+check_trailing_p(Other, State) ->
+    error(garbage_after_command).
+
+error(Reason) ->
+    throw({error, Reason}).
+
+match(State) when State#state.dot == 0 ->
+    false;
+match(State) ->
+    [Line|_] = State#state.upto_dot,
+    Re = State#state.pattern,
+    case regexp:first_match(Line#line.contents, Re) of
+	{match, _, _} -> true;
+	nomatch       -> false
+    end.
+
+skip_blanks([$ |Rest]) ->
+    skip_blanks(Rest);
+skip_blanks(Rest) ->
+    Rest.
+
+print(Rest, [Line], St0) when Line > 0 ->
+    St1 = check_trailing_p(Rest, St0),
+    print(Line, move_to(Line-1, St1));
+print(Rest, [First, Last], St0) when First > 0 ->
+    St1 = check_trailing_p(Rest, St0),
+    print(Last, move_to(First-1, St1)).
+
+print(Last, St) when St#state.dot == Last ->
+    St#state{print=false};
+print(Last, St0) ->
+    St1 = next_line(St0),
+    print_current(St1),
+    print(Last, St1).
+
+lister(Rest, 64) ->
+    io:put_chars("\\\n"),
+    lister(Rest, 0);
+lister([C|Rest], Num) ->
+    list_char(C),
+    lister(Rest, Num+1);
+lister([], _) ->
+    ok.
+
+list_char($\t) ->
+    io:put_chars("\\t");
+list_char($\n) ->
+    io:put_chars("$\n");
+list_char(C) ->
+    io:put_chars([C]).
+
+numberer(Line, St) ->
+    io:format("~w\t~s", [St#state.dot, Line]).
+
+save_for_undo(St) ->
+    St#state{undo=St#state{undo=undefined, print=false}}.
+
+save_for_undo(St, OldSt) ->
+    St#state{undo=OldSt#state{undo=undefined, print=false}}.