indexing
	description: "[
		Commonly used input and output mechanisms.
		This class may be used as either ancestor or supplier
		by classes needing its facilities.
	]"
	library: "Free implementation of ELKS library"
	copyright: "Copyright (c) 1986-2004, Eiffel Software and others"
	license: "Eiffel Forum License v2 (see forum.txt)"
	date: "$Date: 2008-05-23 17:24:07 -0700 (Fri, 23 May 2008) $"
	revision: "$Revision: 170 $"

class interface
	STD_FILES


create 
	default_create
			-- Process instances of classes with no creation clause.
			-- (Default: do nothing.)
			-- (from ANY)

feature -- Access

	default_output: PLAIN_TEXT_FILE
			-- Default output

	error: PLAIN_TEXT_FILE
			-- Standard error file
		ensure
			error_not_void: Result /= Void

	generating_type: STRING_8
			-- Name of current object's generating type
			-- (type of which it is a direct instance)
			-- (from ANY)
		ensure -- from ANY
			generating_type_not_void: Result /= Void
			generating_type_not_empty: not Result.is_empty

	generator: STRING_8
			-- Name of current object's generating class
			-- (base class of the type of which it is a direct instance)
			-- (from ANY)
		ensure -- from ANY
			generator_not_void: Result /= Void
			generator_not_empty: not Result.is_empty

	input: PLAIN_TEXT_FILE
			-- Standard input file
		ensure
			input_not_void: Result /= Void

	output: PLAIN_TEXT_FILE
			-- Standard output file
		ensure
			output_not_void: Result /= Void

	standard_default: PLAIN_TEXT_FILE
			-- Return the default_output or Output
			-- if default_output is Void.
	
feature -- Comparison

	frozen deep_equal (some: ?ANY; other: like arg #1): BOOLEAN
			-- Are `some' and `other' either both void
			-- or attached to isomorphic object structures?
			-- (from ANY)
		ensure -- from ANY
			shallow_implies_deep: standard_equal (some, other) implies Result
			both_or_none_void: (some = Void) implies (Result = (other = Void))
			same_type: (Result and (some /= Void)) implies (other /= Void and then some.same_type (other))
			symmetric: Result implies deep_equal (other, some)

	frozen equal (some: ?ANY; other: like arg #1): BOOLEAN
			-- Are `some' and `other' either both void or attached
			-- to objects considered equal?
			-- (from ANY)
		ensure -- from ANY
			definition: Result = (some = Void and other = Void) or else ((some /= Void and other /= Void) and then some.is_equal (other))

	frozen is_deep_equal (other: STD_FILES): BOOLEAN
			-- Are `Current' and `other' attached to isomorphic object structures?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			shallow_implies_deep: standard_is_equal (other) implies Result
			same_type: Result implies same_type (other)
			symmetric: Result implies other.is_deep_equal (Current)

	is_equal (other: STD_FILES): BOOLEAN
			-- Is `other' attached to an object considered
			-- equal to current object?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			symmetric: Result implies other.is_equal (Current)
			consistent: standard_is_equal (other) implies Result

	frozen standard_equal (some: ?ANY; other: like arg #1): BOOLEAN
			-- Are `some' and `other' either both void or attached to
			-- field-by-field identical objects of the same type?
			-- Always uses default object comparison criterion.
			-- (from ANY)
		ensure -- from ANY
			definition: Result = (some = Void and other = Void) or else ((some /= Void and other /= Void) and then some.standard_is_equal (other))

	frozen standard_is_equal (other: STD_FILES): BOOLEAN
			-- Is `other' attached to an object of the same type
			-- as current object, and field-by-field identical to it?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			same_type: Result implies same_type (other)
			symmetric: Result implies other.standard_is_equal (Current)
	
feature -- Status report

	conforms_to (other: ANY): BOOLEAN
			-- Does type of current object conform to type
			-- of `other' (as per Eiffel: The Language, chapter 13)?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void

	last_character: CHARACTER_8
			-- Last character read by read_character
			-- Was declared in STD_FILES as synonym of lastchar.

	last_double: REAL_64
			-- Last double read by read_double
			-- Was declared in STD_FILES as synonym of lastdouble.

	last_integer: INTEGER_32
			-- Last integer read by read_integer
			-- Was declared in STD_FILES as synonym of lastint and last_integer_32.

	last_integer_16: INTEGER_16
			-- Last 16-bit integer read by read_integer_16

	last_integer_32: INTEGER_32
			-- Last integer read by read_integer
			-- Was declared in STD_FILES as synonym of last_integer and lastint.

	last_integer_64: INTEGER_64
			-- Last 8-bit integer read by read_integer_64

	last_integer_8: INTEGER_8
			-- Last 8-bit integer read by read_integer_8

	last_natural: NATURAL_32
			-- Last 32-bit natural read by read_natural_32
			-- Was declared in STD_FILES as synonym of last_natural_32.

	last_natural_16: NATURAL_16
			-- Last 16-bit natural read by read_natural_16

	last_natural_32: NATURAL_32
			-- Last 32-bit natural read by read_natural_32
			-- Was declared in STD_FILES as synonym of last_natural.

	last_natural_64: NATURAL_64
			-- Last 64-bit natural read by read_natural_64

	last_natural_8: NATURAL_8
			-- Last 8-bit natural read by read_natural_8

	last_real: REAL_32
			-- Last real read by read_real
			-- Was declared in STD_FILES as synonym of lastreal.

	last_string: ?STRING_8
			-- Last string read by read_line,
			-- read_stream, or read_word
			-- Was declared in STD_FILES as synonym of laststring.

	lastchar: CHARACTER_8
			-- Last character read by read_character
			-- Was declared in STD_FILES as synonym of last_character.

	lastdouble: REAL_64
			-- Last double read by read_double
			-- Was declared in STD_FILES as synonym of last_double.

	lastint: INTEGER_32
			-- Last integer read by read_integer
			-- Was declared in STD_FILES as synonym of last_integer and last_integer_32.

	lastreal: REAL_32
			-- Last real read by read_real
			-- Was declared in STD_FILES as synonym of last_real.

	laststring: ?STRING_8
			-- Last string read by read_line,
			-- read_stream, or read_word
			-- Was declared in STD_FILES as synonym of last_string.

	same_type (other: ANY): BOOLEAN
			-- Is type of current object identical to type of `other'?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			definition: Result = (conforms_to (other) and other.conforms_to (Current))
	
feature -- Element change

	new_line
			-- Write line feed at end of default output.
			-- Was declared in STD_FILES as synonym of put_new_line.

	put_boolean (b: BOOLEAN)
			-- Write `b' at end of default output.
			-- Was declared in STD_FILES as synonym of putbool.

	put_character (c: CHARACTER_8)
			-- Write `c' at end of default output.
			-- Was declared in STD_FILES as synonym of putchar.

	put_double (d: REAL_64)
			-- Write `d' at end of default output.
			-- Was declared in STD_FILES as synonym of putdouble.

	put_integer (i: INTEGER_32)
			-- Write `i' at end of default output.
			-- Was declared in STD_FILES as synonym of putint and put_integer_32.

	put_integer_16 (i: INTEGER_16)
			-- Write `i' at end of default output.

	put_integer_32 (i: INTEGER_32)
			-- Write `i' at end of default output.
			-- Was declared in STD_FILES as synonym of put_integer and putint.

	put_integer_64 (i: INTEGER_64)
			-- Write `i' at end of default output.

	put_integer_8 (i: INTEGER_8)
			-- Write `i' at end of default output.

	put_natural (i: NATURAL_32)
			-- Write `i' at end of default output.
			-- Was declared in STD_FILES as synonym of put_natural_32.

	put_natural_16 (i: NATURAL_16)
			-- Write `i' at end of default output.

	put_natural_32 (i: NATURAL_32)
			-- Write `i' at end of default output.
			-- Was declared in STD_FILES as synonym of put_natural.

	put_natural_64 (i: NATURAL_64)
			-- Write `i' at end of default output.

	put_natural_8 (i: NATURAL_8)
			-- Write `i' at end of default output.

	put_new_line
			-- Write line feed at end of default output.
			-- Was declared in STD_FILES as synonym of new_line.

	put_real (r: REAL_32)
			-- Write `r' at end of default output.
			-- Was declared in STD_FILES as synonym of putreal.

	put_string (s: STRING_8)
			-- Write `s' at end of default output.
			-- Was declared in STD_FILES as synonym of putstring.
		require
			string_not_void: s /= Void

	putbool (b: BOOLEAN)
			-- Write `b' at end of default output.
			-- Was declared in STD_FILES as synonym of put_boolean.

	putchar (c: CHARACTER_8)
			-- Write `c' at end of default output.
			-- Was declared in STD_FILES as synonym of put_character.

	putdouble (d: REAL_64)
			-- Write `d' at end of default output.
			-- Was declared in STD_FILES as synonym of put_double.

	putint (i: INTEGER_32)
			-- Write `i' at end of default output.
			-- Was declared in STD_FILES as synonym of put_integer and put_integer_32.

	putreal (r: REAL_32)
			-- Write `r' at end of default output.
			-- Was declared in STD_FILES as synonym of put_real.

	putstring (s: STRING_8)
			-- Write `s' at end of default output.
			-- Was declared in STD_FILES as synonym of put_string.
		require
			string_not_void: s /= Void

	set_error_default
			-- Use standard error as default output.

	set_file_default (f: PLAIN_TEXT_FILE)
			-- Use `f' as default output.
		require
			valid_argument: f /= Void
			file_open_write: f.is_open_write

	set_output_default
			-- Use standard output as default output.
	
feature -- Duplication

	copy (other: STD_FILES)
			-- Update current object using fields of object attached
			-- to `other', so as to yield equal objects.
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
			type_identity: same_type (other)
		ensure -- from ANY
			is_equal: is_equal (other)

	frozen deep_copy (other: STD_FILES)
			-- Effect equivalent to that of:
			--		copy (`other' . deep_twin)
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			deep_equal: deep_equal (Current, other)

	frozen deep_twin: STD_FILES
			-- New object structure recursively duplicated from Current.
			-- (from ANY)
		ensure -- from ANY
			deep_twin_not_void: Result /= Void
			deep_equal: deep_equal (Current, Result)

	frozen standard_copy (other: STD_FILES)
			-- Copy every field of `other' onto corresponding field
			-- of current object.
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
			type_identity: same_type (other)
		ensure -- from ANY
			is_standard_equal: standard_is_equal (other)

	frozen standard_twin: STD_FILES
			-- New object field-by-field identical to `other'.
			-- Always uses default copying semantics.
			-- (from ANY)
		ensure -- from ANY
			standard_twin_not_void: Result /= Void
			equal: standard_equal (Result, Current)

	frozen twin: STD_FILES
			-- New object equal to `Current'
			-- twin calls copy; to change copying/twining semantics, redefine copy.
			-- (from ANY)
		ensure -- from ANY
			twin_not_void: Result /= Void
			is_equal: Result.is_equal (Current)
	
feature -- Basic operations

	frozen default: ?STD_FILES
			-- Default value of object's type
			-- (from ANY)

	frozen default_pointer: POINTER
			-- Default value of type `POINTER'
			-- (Avoid the need to write `p'.default for
			-- some `p' of type `POINTER'.)
			-- (from ANY)

	default_rescue
			-- Process exception for routines with no Rescue clause.
			-- (Default: do nothing.)
			-- (from ANY)

	frozen do_nothing
			-- Execute a null action.
			-- (from ANY)
	
feature -- Input

	next_line
			-- Move to next input line on standard input.
			-- Was declared in STD_FILES as synonym of to_next_line.

	read_character
			-- Read a new character from standard input.
			-- It will not return until read operation is
			-- terminated when enter key is pressed.
			-- Make result available in last_character.
			-- last_character will also contains platform
			-- specific newline character.
			-- Was declared in STD_FILES as synonym of readchar.

	read_double
			-- Read a new double from standard input.
			-- Make result available in last_double.
			-- Was declared in STD_FILES as synonym of readdouble.

	read_integer
			-- Read a new 32-bit integer from standard input.
			-- Make result available in last_integer.
			-- Was declared in STD_FILES as synonym of readint and read_integer_32.

	read_integer_16
			-- Read a new 16-bit integer from standard input.
			-- Make result available in last_integer_16.

	read_integer_32
			-- Read a new 32-bit integer from standard input.
			-- Make result available in last_integer.
			-- Was declared in STD_FILES as synonym of read_integer and readint.

	read_integer_64
			-- Read a new 64-bit integer from standard input.
			-- Make result available in last_integer_64.

	read_integer_8
			-- Read a new 8-bit integer from standard input.
			-- Make result available in last_integer_8.

	read_line
			-- Read a line from standard input.
			-- Make result available in last_string.
			-- Was declared in STD_FILES as synonym of readline.
		ensure
			last_string_not_void: last_string /= Void

	read_natural
			-- Read a new 32-bit natural from standard input.
			-- Make result available in last_natural.
			-- Was declared in STD_FILES as synonym of read_natural_32.

	read_natural_16
			-- Read a new 16-bit natural from standard input.
			-- Make result available in last_natural_16.

	read_natural_32
			-- Read a new 32-bit natural from standard input.
			-- Make result available in last_natural.
			-- Was declared in STD_FILES as synonym of read_natural.

	read_natural_64
			-- Read a new 64-bit natural from standard input.
			-- Make result available in last_natural_64.

	read_natural_8
			-- Read a new 8-bit natural from standard input.
			-- Make result available in last_natural_8.

	read_real
			-- Read a new real from standard input.
			-- Make result available in last_real.
			-- Was declared in STD_FILES as synonym of readreal.

	read_stream (nb_char: INTEGER_32)
			-- Read a string of at most `nb_char' bound characters
			-- from standard input.
			-- Make result available in last_string.
			-- Was declared in STD_FILES as synonym of readstream.
		ensure
			last_string_not_void: last_string /= Void

	read_word
			-- Read a new word from standard input.
			-- Make result available in last_string.
			-- Was declared in STD_FILES as synonym of readword.
		ensure
			last_string_not_void: last_string /= Void

	readchar
			-- Read a new character from standard input.
			-- It will not return until read operation is
			-- terminated when enter key is pressed.
			-- Make result available in last_character.
			-- last_character will also contains platform
			-- specific newline character.
			-- Was declared in STD_FILES as synonym of read_character.

	readdouble
			-- Read a new double from standard input.
			-- Make result available in last_double.
			-- Was declared in STD_FILES as synonym of read_double.

	readint
			-- Read a new 32-bit integer from standard input.
			-- Make result available in last_integer.
			-- Was declared in STD_FILES as synonym of read_integer and read_integer_32.

	readline
			-- Read a line from standard input.
			-- Make result available in last_string.
			-- Was declared in STD_FILES as synonym of read_line.
		ensure
			last_string_not_void: last_string /= Void

	readreal
			-- Read a new real from standard input.
			-- Make result available in last_real.
			-- Was declared in STD_FILES as synonym of read_real.

	readstream (nb_char: INTEGER_32)
			-- Read a string of at most `nb_char' bound characters
			-- from standard input.
			-- Make result available in last_string.
			-- Was declared in STD_FILES as synonym of read_stream.
		ensure
			last_string_not_void: last_string /= Void

	readword
			-- Read a new word from standard input.
			-- Make result available in last_string.
			-- Was declared in STD_FILES as synonym of read_word.
		ensure
			last_string_not_void: last_string /= Void

	to_next_line
			-- Move to next input line on standard input.
			-- Was declared in STD_FILES as synonym of next_line.
	
feature -- Output

	io: STD_FILES
			-- Handle to standard file setup
			-- (from ANY)
		ensure -- from ANY
			io_not_void: Result /= Void

	out: STRING_8
			-- New string containing terse printable representation
			-- of current object
			-- (from ANY)
		ensure -- from ANY
			out_not_void: Result /= Void

	print (some: ?ANY)
			-- Write terse external representation of `some'
			-- on standard output.
			-- (from ANY)

	frozen tagged_out: STRING_8
			-- New string containing terse printable representation
			-- of current object
			-- (from ANY)
		ensure -- from ANY
			tagged_out_not_void: Result /= Void
	
feature -- Platform

	operating_environment: OPERATING_ENVIRONMENT
			-- Objects available from the operating system
			-- (from ANY)
		ensure -- from ANY
			operating_environment_not_void: Result /= Void
	
invariant
		-- from ANY
	reflexive_equality: standard_is_equal (Current)
	reflexive_conformance: conforms_to (Current)

end -- class STD_FILES