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102 lines
3.3 KiB
Mathematica
102 lines
3.3 KiB
Mathematica
%-----------------------------------------------------------------------------%
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% Copyright (C) 1995 University of Melbourne.
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% This file may only be copied under the terms of the GNU General
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% Public License - see the file COPYING in the Mercury distribution.
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%-----------------------------------------------------------------------------%
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:- module file.
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:- interface.
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% Main author: bromage
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:- import_module io, list, string.
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:- type file.
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% file__read_file reads a file from a filename.
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:- pred file__read_file(string, io__res(file), io__state, io__state).
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:- mode file__read_file(in, out, di, uo) is det.
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% file__read_input reads a file from the input
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% stream.
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:- pred file__read_input(io__res(file), io__state, io__state).
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:- mode file__read_input(out, di, uo) is det.
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% file__get_line retrieves a line from a file.
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% Fails if the line is out of bounds.
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:- pred file__get_line(file, int, string).
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:- mode file__get_line(in, in, out) is semidet.
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% file__get_numlines returns the number of lines
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% in a file.
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:- pred file__get_numlines(file, int).
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:- mode file__get_numlines(in, out) is det.
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% file__to_list converts a file into a list of
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% lines.
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:- pred file__to_list(file, list(string)).
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:- mode file__to_list(in, out) is det.
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%-----------------------------------------------------------------------------%
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:- implementation.
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:- import_module array, require, int.
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%-----------------------------------------------------------------------------%
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:- type file == array(string).
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% Open the stream, read from the stream, then close
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% the stream.
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file__read_file(FileName, Contents) -->
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io__open_input(FileName, Res),
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( { Res = ok(InputStream) },
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file__read_stream(InputStream, Contents0),
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io__close_input(InputStream),
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{ Contents = ok(Contents0) }
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; { Res = error(Error) },
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{ Contents = error(Error) }
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).
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% Get the input stream, then read from it.
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file__read_input(ok(Contents)) -->
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io__input_stream(InputStream),
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file__read_stream(InputStream, Contents).
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% file__read_stream is the "real" file reader.
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:- pred file__read_stream(io__input_stream, file, io__state, io__state).
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:- mode file__read_stream(in, out, di, uo) is det.
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file__read_stream(Stream, File) -->
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file__read_stream2(Stream, 0, _, File).
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:- pred file__read_stream2(io__input_stream, int, int, file,
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io__state, io__state).
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:- mode file__read_stream2(in, in, out, out, di, uo) is det.
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file__read_stream2(Stream, LinesIn, LinesOut, File) -->
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io__read_line(Stream, Res),
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( { Res = eof },
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{ LinesOut = LinesIn },
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{ array__init(1, LinesOut, "", File) }
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; { Res = ok(Line) },
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{ LinesIn1 is LinesIn + 1 },
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{ string__from_char_list(Line, Line1) },
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file__read_stream2(Stream, LinesIn1, LinesOut, File1),
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{ array__set(File1, LinesIn1, Line1, File) }
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; { Res = error(Error) },
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{ io__error_message(Error, Msg) },
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{ error(Msg) }
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).
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%-----------------------------------------------------------------------------%
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file__get_line(File, LineNo, Line) :-
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array__semidet_lookup(File, LineNo, Line).
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file__get_numlines(File, NumLines) :-
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array__bounds(File, _, NumLines).
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file__to_list(File, List) :-
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array__to_list(File, List).
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%-----------------------------------------------------------------------------%
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%-----------------------------------------------------------------------------%
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