Files
mercury/samples/diff/diff.m
1995-06-16 06:46:32 +00:00

121 lines
3.7 KiB
Mathematica

%-----------------------------------------------------------------------------%
% Copyright (C) 1995 University of Melbourne.
% This file may only be copied under the terms of the GNU General
% Public License - see the file COPYING in the Mercury distribution.
%-----------------------------------------------------------------------------%
% File: diff.m
% Main author: bromage
% Something very similar to the standard diff utility. Sort of. :-)
% On the still-to-do list:
% - Add command-line options. Probably:
% --ignore-all-space
% --ignore-blank-lines
% --ignore-case
% --rcs
% What others are easy and don't break up the code?
:- module diff.
:- interface.
:- import_module io.
:- pred main(io__state :: di, io__state :: uo) is det.
%-----------------------------------------------------------------------------%
:- implementation.
:- import_module string, list, file, lcss, std_util, require.
%-----------------------------------------------------------------------------%
% main: top-level predicate.
main -->
io__command_line_arguments(Args0),
% { getopt__process_options(Args0, Args, Result0) },
% postprocess_options(Result0, Result),
% main_2(Result, Args).
main_2(no, Args0).
%-----------------------------------------------------------------------------%
:- pred usage_error(string :: in, io__state :: di, io__state :: uo) is det.
usage_error(Msg) -->
io__progname_base("diff", ProgName),
io__stderr_stream(StdErr),
io__write_strings(StdErr, [ProgName, ": ", Msg, "\n"]),
io__set_exit_status(1),
usage.
:- pred usage_io_error(io__error, io__state, io__state).
:- mode usage_io_error(in, di, uo) is det.
usage_io_error(Error) -->
{ io__error_message(Error, Msg) },
usage_error(Msg).
:- pred usage(io__state :: di, io__state :: uo) is det.
usage -->
io__write_string("Usage: diff [options] from-file to-file\n"),
io__write_string("Options:\n"),
io__write_string("\tnone yet :-)\n").
%-----------------------------------------------------------------------------%
% main_2
:- pred main_2(maybe(string), list(string), io__state, io__state).
:- mode main_2(in, in, di, uo) is det.
main_2(yes(Msg), _) -->
usage_error(Msg).
main_2(no, []) -->
usage_error("missing operand").
main_2(no, [Fname1 | Rest]) -->
( { Rest = [Fname2 | _] },
( { Fname1 = Fname2 } ->
% There are no differences between identical files.
[]
;
% If either file is "-", simply use standard input.
% (Note: Both can't be "-" since that was dealt with
% in the previous case.)
( { Fname1 = "-" } ->
file__read_input(Contents1),
file__read_file(Fname2, Contents2)
; { Fname2 = "-" } ->
file__read_file(Fname1, Contents1),
file__read_input(Contents2)
;
% Otherwise read the files normally.
file__read_file(Fname1, Contents1),
file__read_file(Fname2, Contents2)
),
% Now do the diff.
( { Contents1 = ok(File1), Contents2 = ok(File2) } ->
diff__do_diff(File1, File2)
; { Contents1 = error(Msg) } ->
usage_io_error(Msg)
; { Contents2 = error(Msg) } ->
usage_io_error(Msg)
;
{ error("main2") }
)
)
; { Rest = [] },
usage_error("missing operand")
).
%-----------------------------------------------------------------------------%
% diff__do_diff takes the files plus all the command
% line options (all zero of them) and determines what
% to do with them.
:- pred diff__do_diff(file, file, io__state, io__state).
:- mode diff__do_diff(in, in, di, uo) is det.
diff__do_diff(File1, File2) -->
{ lcss__find_diff(File1, File2, Diff) },
lcss__display_diff(File1, File2, Diff).
%-----------------------------------------------------------------------------%
%-----------------------------------------------------------------------------%