note
	description: "[
		Commonly used console input and output mechanisms. 
		This class may be used as ancestor by classes needing its facilities.
	]"
	library: "Free implementation of ELKS library"
	status: "See notice at end of class."
	legal: "See notice at end of class."
	date: "$Date: 2018-10-03 14:39:27 +0000 (Wed, 03 Oct 2018) $"
	revision: "$Revision: 102265 $"

class interface
	CONSOLE

create {STD_FILES}
	make_open_stdin (fn: READABLE_STRING_GENERAL)
			-- Create a standard input file.
		require -- from FILE
			string_exists: fn /= Void
			string_not_empty: not fn.is_empty
		ensure -- from FILE
			file_named: internal_name = fn
			exists: exists
			open_read: is_open_read

	make_open_stdout (fn: READABLE_STRING_GENERAL)
			-- Create a standard output file.
		require -- from FILE
			string_exists: fn /= Void
			string_not_empty: not fn.is_empty
		ensure -- from FILE
			file_named: internal_name = fn
			exists: exists
			open_write: is_open_write

	make_open_stderr (fn: READABLE_STRING_GENERAL)
			-- Create a standard error file.

feature -- Initialization

	make_open_stderr (fn: READABLE_STRING_GENERAL)
			-- Create a standard error file.

	make_open_stdin (fn: READABLE_STRING_GENERAL)
			-- Create a standard input file.
		require -- from FILE
			string_exists: fn /= Void
			string_not_empty: not fn.is_empty
		ensure -- from FILE
			file_named: internal_name = fn
			exists: exists
			open_read: is_open_read

	make_open_stdout (fn: READABLE_STRING_GENERAL)
			-- Create a standard output file.
		require -- from FILE
			string_exists: fn /= Void
			string_not_empty: not fn.is_empty
		ensure -- from FILE
			file_named: internal_name = fn
			exists: exists
			open_write: is_open_write
	
feature -- Access

	file_pointer: POINTER
			-- File pointer as required in C
			-- (from FILE)

	generating_type: TYPE [detachable CONSOLE]
			-- Type of current object
			-- (type of which it is a direct instance)
			-- (from ANY)
		ensure -- from ANY
			generating_type_not_void: Result /= Void

	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

	separator: CHARACTER_8
			-- ASCII code of character following last word read
			-- (from FILE)
	
feature -- Comparison

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

	frozen equal (a: detachable ANY; b: like arg #1): BOOLEAN
			-- Are a and b either both void or attached
			-- to objects considered equal?
			-- (from ANY)
		ensure -- from ANY
			instance_free: class
			definition: Result = (a = Void and b = Void) or else ((a /= Void and b /= Void) and then a.is_equal (b))

	frozen is_deep_equal (other: CONSOLE): 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: CONSOLE): 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 ~ Current
			consistent: standard_is_equal (other) implies Result

	frozen standard_equal (a: detachable ANY; b: like arg #1): BOOLEAN
			-- Are a and b 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
			instance_free: class
			definition: Result = (a = Void and b = Void) or else ((a /= Void and b /= Void) and then a.standard_is_equal (b))

	frozen standard_is_equal (other: CONSOLE): 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

	Count: INTEGER_32 = 1
			-- Useless for CONSOLE class.

	end_of_file: BOOLEAN
			-- Have we reached the end of file?
		require -- from FILE
			opened: not is_closed

	exists: BOOLEAN
			-- Does file exist?
		require -- from  IO_MEDIUM
			True
		ensure then -- from FILE
			unchanged_mode: mode = old mode

	extendible: BOOLEAN
			-- May new items be added?
			-- (from FILE)
		require -- from  COLLECTION
			True
		require -- from  IO_MEDIUM
			True

	file_readable: BOOLEAN
			-- Is there a current item that may be read?
			-- (from FILE)

	is_closed: BOOLEAN
			-- Is file closed?
			-- (from FILE)

	is_open_write: BOOLEAN
			-- Is file open for writing?
			-- (from FILE)

	last_character: CHARACTER_8
			-- Last character read by read_character
			-- (from IO_MEDIUM)

	last_double: REAL_64
			-- Last double read by read_double
			-- (from IO_MEDIUM)

	last_integer: INTEGER_32
			-- Last integer read by read_integer
			-- (from IO_MEDIUM)

	last_integer_16: INTEGER_16
			-- Last 16-bit integer read by read_integer_16
			-- (from IO_MEDIUM)

	last_integer_32: INTEGER_32
			-- Synonymy of last_integer
			-- (from IO_MEDIUM)

	last_integer_64: INTEGER_64
			-- Last 64-bit integer read by read_integer_64
			-- (from IO_MEDIUM)

	last_integer_8: INTEGER_8
			-- Last 8-bit integer read by read_integer_8
			-- (from IO_MEDIUM)

	last_natural: NATURAL_32
			-- Last 32-bit natural read by read_natural
			-- (from IO_MEDIUM)

	last_natural_16: NATURAL_16
			-- Last 16-bit natural read by read_natural_16
			-- (from IO_MEDIUM)

	last_natural_32: NATURAL_32
			-- Synonymy of last_natural
			-- (from IO_MEDIUM)

	last_natural_64: NATURAL_64
			-- Last 64-bit natural read by read_natural_64
			-- (from IO_MEDIUM)

	last_natural_8: NATURAL_8
			-- Last 8-bit natural read by read_natural_8
			-- (from IO_MEDIUM)

	last_real: REAL_32
			-- Last real read by read_real
			-- (from IO_MEDIUM)

	last_string: STRING_8
			-- Last string read
			-- (from IO_MEDIUM)

	readable: BOOLEAN
			-- Is there a current item that may be read?
			-- (from SEQUENCE)
		require -- from  ACTIVE
			True
		require -- from IO_MEDIUM
			handle_exists: exists

	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

	append (f: CONSOLE)
			-- Append a copy of the contents of f.
			-- (from FILE)
		require -- from SEQUENCE
			argument_not_void: f /= Void
		require else -- from FILE
			target_is_closed: is_closed
			source_is_closed: f.is_closed
		ensure -- from SEQUENCE
			new_count: Count >= old Count
		ensure then -- from FILE
			new_count: Count = old Count + f.Count
			files_closed: f.is_closed and is_closed
	
feature -- Removal

	dispose
			-- This is closed by the operating system at completion.
		require -- from  DISPOSABLE
			True
	
feature -- Duplication

	copy (other: CONSOLE)
			-- 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: Current ~ other

	frozen deep_copy (other: CONSOLE)
			-- 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: CONSOLE
			-- 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: CONSOLE)
			-- 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: CONSOLE
			-- 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: CONSOLE
			-- New object equal to Current
			-- twin calls copy; to change copying/twinning semantics, redefine copy.
			-- (from ANY)
		ensure -- from ANY
			twin_not_void: Result /= Void
			is_equal: Result ~ Current
	
feature -- Basic operations

	frozen default: detachable CONSOLE
			-- 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)
		ensure -- from ANY
			instance_free: class

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

	frozen do_nothing
			-- Execute a null action.
			-- (from ANY)
		ensure -- from ANY
			instance_free: class
	
feature -- Obsolete

	lastchar: CHARACTER_8
			-- Last character read by read_character
			-- (from IO_MEDIUM)

	lastdouble: REAL_64
			-- Last double read by read_double
			-- (from IO_MEDIUM)

	lastint: INTEGER_32
			-- Last integer read by read_integer
			-- (from IO_MEDIUM)

	lastreal: REAL_32
			-- Last real read by read_real
			-- (from IO_MEDIUM)

	laststring: like last_string
			-- Last string read
			-- (from IO_MEDIUM)
	
feature -- Input

	next_line
			-- Move to next input line on standard input.
		require -- from FILE
			is_readable: file_readable

	read_character
			-- Read a new character from standard input.
			-- Make result available in last_character.
			-- Was declared in CONSOLE as synonym of readchar.
		require -- from IO_MEDIUM
			is_readable: readable
		require else -- from FILE
			is_readable: file_readable

	read_double
			-- Read a new double from standard input.
			-- Make result available in last_double.
			-- Was declared in CONSOLE as synonym of readdouble.
		require -- from IO_MEDIUM
			is_readable: readable
		require else -- from FILE
			is_readable: file_readable

	read_integer
			-- Read the ASCII representation of a new 32-bit integer
			-- from file. Make result available in last_integer.
			-- Was declared in PLAIN_TEXT_FILE as synonym of readint and read_integer_32.
			-- (from PLAIN_TEXT_FILE)
		require -- from IO_MEDIUM
			is_readable: readable
		require else -- from FILE
			is_readable: file_readable

	read_integer_16
			-- Read the ASCII representation of a new 16-bit integer
			-- from file. Make result available in last_integer_16.
			-- (from PLAIN_TEXT_FILE)
		require -- from IO_MEDIUM
			is_readable: readable

	read_integer_32
			-- Read the ASCII representation of a new 32-bit integer
			-- from file. Make result available in last_integer.
			-- Was declared in PLAIN_TEXT_FILE as synonym of read_integer and readint.
			-- (from PLAIN_TEXT_FILE)
		require -- from IO_MEDIUM
			is_readable: readable

	read_integer_64
			-- (from PLAIN_TEXT_FILE)
		require -- from IO_MEDIUM
			is_readable: readable

	read_integer_8
			-- Read the ASCII representation of a new 8-bit integer
			-- from file. Make result available in last_integer_8.
			-- (from PLAIN_TEXT_FILE)
		require -- from IO_MEDIUM
			is_readable: readable

	read_line
			-- Read a string until new line or end of file.
			-- Make result available in last_string.
			-- New line will be consumed but not part of last_string.
			-- Was declared in CONSOLE as synonym of readline.
		require -- from IO_MEDIUM
			is_readable: readable
		require else -- from FILE
			is_readable: file_readable
		require else
			is_readable: file_readable
		ensure -- from IO_MEDIUM
			last_string_not_void: last_string /= Void

	read_line_thread_aware
			-- Read characters until a new line or
			-- end of medium.
			-- Make result available in last_string.
			-- Functionally identical to read_line but
			-- won't prevent garbage collection from occurring
			-- while blocked waiting for data, though data must
			-- be copied an extra time.			
		require -- from IO_MEDIUM
			is_readable: readable
		require else -- from FILE
			is_readable: file_readable
		require else
			is_readable: file_readable
		ensure -- from IO_MEDIUM
			last_string_not_void: last_string /= Void

	read_natural
			-- Read the ASCII representation of a new 32-bit natural
			-- from file. Make result available in last_natural.
			-- Was declared in PLAIN_TEXT_FILE as synonym of read_natural_32.
			-- (from PLAIN_TEXT_FILE)
		require -- from IO_MEDIUM
			is_readable: readable

	read_natural_16
			-- Read the ASCII representation of a new 16-bit natural
			-- from file. Make result available in last_natural_16.
			-- (from PLAIN_TEXT_FILE)
		require -- from IO_MEDIUM
			is_readable: readable

	read_natural_32
			-- Read the ASCII representation of a new 32-bit natural
			-- from file. Make result available in last_natural.
			-- Was declared in PLAIN_TEXT_FILE as synonym of read_natural.
			-- (from PLAIN_TEXT_FILE)
		require -- from IO_MEDIUM
			is_readable: readable

	read_natural_64
			-- Read the ASCII representation of a new 64-bit natural
			-- from file. Make result available in last_natural_64.
			-- (from PLAIN_TEXT_FILE)
		require -- from IO_MEDIUM
			is_readable: readable

	read_natural_8
			-- Read the ASCII representation of a new 8-bit natural
			-- from file. Make result available in last_natural_8.
			-- (from PLAIN_TEXT_FILE)
		require -- from IO_MEDIUM
			is_readable: readable

	read_real
			-- Read a new real from standard input.
			-- Make result available in last_real.
			-- Was declared in CONSOLE as synonym of readreal.
		require -- from IO_MEDIUM
			is_readable: readable
		require else -- from FILE
			is_readable: file_readable

	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 CONSOLE as synonym of readstream.
		require -- from IO_MEDIUM
			is_readable: readable
		require else -- from FILE
			is_readable: file_readable
		ensure -- from IO_MEDIUM
			last_string_not_void: last_string /= Void

	read_stream_thread_aware (nb_char: INTEGER_32)
			-- Read a string of at most nb_char bound characters
			-- or until end of medium is encountered.
			-- Make result available in last_string.
			-- Functionally identical to read_stream but
			-- won't prevent garbage collection from occurring
			-- while blocked waiting for data, though data must
			-- be copied an extra time.			
		require -- from IO_MEDIUM
			is_readable: readable
		require else -- from FILE
			is_readable: file_readable
		ensure -- from IO_MEDIUM
			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 CONSOLE as synonym of readword.
		require -- from FILE
			is_readable: file_readable
		ensure -- from FILE
			last_string_not_void: last_string /= Void

	read_word_thread_aware
			-- Read a string, excluding white space and stripping
			-- leading white space.
			-- Make result available in last_string.
			-- White space characters are: blank, new_line, tab,
			-- vertical tab, formfeed, end of file.
		require -- from FILE
			is_readable: file_readable
		ensure -- from FILE
			last_string_not_void: last_string /= Void

	readchar
			-- Read a new character from standard input.
			-- Make result available in last_character.
			-- Was declared in CONSOLE as synonym of read_character.
		require -- from IO_MEDIUM
			is_readable: readable
		require else -- from FILE
			is_readable: file_readable

	readdouble
			-- Read a new double from standard input.
			-- Make result available in last_double.
			-- Was declared in CONSOLE as synonym of read_double.
		require -- from IO_MEDIUM
			is_readable: readable
		require else -- from FILE
			is_readable: file_readable

	readint
			-- Read the ASCII representation of a new 32-bit integer
			-- from file. Make result available in last_integer.
			-- Was declared in PLAIN_TEXT_FILE as synonym of read_integer and read_integer_32.
			-- (from PLAIN_TEXT_FILE)
		require -- from IO_MEDIUM
			is_readable: readable
		require else -- from FILE
			is_readable: file_readable

	readline
			-- Read a string until new line or end of file.
			-- Make result available in last_string.
			-- New line will be consumed but not part of last_string.
			-- Was declared in CONSOLE as synonym of read_line.
		require -- from IO_MEDIUM
			is_readable: readable
		require else -- from FILE
			is_readable: file_readable
		require else
			is_readable: file_readable
		ensure -- from IO_MEDIUM
			last_string_not_void: last_string /= Void

	readreal
			-- Read a new real from standard input.
			-- Make result available in last_real.
			-- Was declared in CONSOLE as synonym of read_real.
		require -- from IO_MEDIUM
			is_readable: readable
		require else -- from FILE
			is_readable: file_readable

	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 CONSOLE as synonym of read_stream.
		require -- from IO_MEDIUM
			is_readable: readable
		require else -- from FILE
			is_readable: file_readable
		ensure -- from IO_MEDIUM
			last_string_not_void: last_string /= Void

	readword
			-- Read a new word from standard input.
			-- Make result available in last_string.
			-- Was declared in CONSOLE as synonym of read_word.
		require -- from FILE
			is_readable: file_readable
		ensure -- from FILE
			last_string_not_void: last_string /= Void
	
feature -- Iteration

	new_cursor: FILE_ITERATION_CURSOR
			-- Fresh cursor associated with current structure
		require -- from  ITERABLE
			True
		ensure -- from ITERABLE
			result_attached: Result /= Void
	
feature -- Output

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

	new_line
			-- Write line feed at end of default output.
			-- Was declared in CONSOLE as synonym of put_new_line.
		require -- from IO_MEDIUM
			extendible: extendible

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

	print (o: detachable ANY)
			-- Write terse external representation of o
			-- on standard output.
			-- (from ANY)
		ensure -- from ANY
			instance_free: class

	put_boolean (b: BOOLEAN)
			-- Write b at end of default output.
			-- Was declared in CONSOLE as synonym of putbool.
		require -- from IO_MEDIUM
			extendible: extendible

	put_character (c: CHARACTER_8)
			-- Write c at end of default output.
			-- Was declared in CONSOLE as synonym of putchar.
		require -- from IO_MEDIUM
			extendible: extendible

	put_double (d: REAL_64)
			-- Write d at end of default output.
			-- Was declared in CONSOLE as synonym of putdouble.
		require -- from IO_MEDIUM
			extendible: extendible

	put_integer (i: INTEGER_32)
			-- Write ASCII value of i at current position.
			-- Was declared in PLAIN_TEXT_FILE as synonym of putint and put_integer_32.
			-- (from PLAIN_TEXT_FILE)
		require -- from IO_MEDIUM
			extendible: extendible

	put_integer_16 (i: INTEGER_16)
			-- Write ASCII value of i at current position.
			-- (from PLAIN_TEXT_FILE)
		require -- from IO_MEDIUM
			extendible: extendible

	put_integer_32 (i: INTEGER_32)
			-- Write ASCII value of i at current position.
			-- Was declared in PLAIN_TEXT_FILE as synonym of put_integer and putint.
			-- (from PLAIN_TEXT_FILE)
		require -- from IO_MEDIUM
			extendible: extendible

	put_integer_64 (i: INTEGER_64)
			-- Write ASCII value of i at current position.
			-- (from PLAIN_TEXT_FILE)
		require -- from IO_MEDIUM
			extendible: extendible

	put_integer_8 (i: INTEGER_8)
			-- Write ASCII value of i at current position.
			-- (from PLAIN_TEXT_FILE)
		require -- from IO_MEDIUM
			extendible: extendible

	put_natural (i: NATURAL_32)
			-- Write ASCII value of i at current position.
			-- Was declared in PLAIN_TEXT_FILE as synonym of put_natural_32.
			-- (from PLAIN_TEXT_FILE)
		require -- from IO_MEDIUM
			extendible: extendible

	put_natural_16 (i: NATURAL_16)
			-- Write ASCII value of i at current position.
			-- (from PLAIN_TEXT_FILE)
		require -- from IO_MEDIUM
			extendible: extendible

	put_natural_32 (i: NATURAL_32)
			-- Write ASCII value of i at current position.
			-- Was declared in PLAIN_TEXT_FILE as synonym of put_natural.
			-- (from PLAIN_TEXT_FILE)
		require -- from IO_MEDIUM
			extendible: extendible

	put_natural_64 (i: NATURAL_64)
			-- Write ASCII value of i at current position.
			-- (from PLAIN_TEXT_FILE)
		require -- from IO_MEDIUM
			extendible: extendible

	put_natural_8 (i: NATURAL_8)
			-- Write ASCII value of i at current position.
			-- (from PLAIN_TEXT_FILE)
		require -- from IO_MEDIUM
			extendible: extendible

	put_new_line
			-- Write line feed at end of default output.
			-- Was declared in CONSOLE as synonym of new_line.
		require -- from IO_MEDIUM
			extendible: extendible

	put_real (r: REAL_32)
			-- Write r at end of default output.
			-- Was declared in CONSOLE as synonym of putreal.
		require -- from IO_MEDIUM
			extendible: extendible

	put_string (s: STRING_8)
			-- Write s at end of default output.
			-- Was declared in CONSOLE as synonym of putstring.
		require -- from IO_MEDIUM
			extendible: extendible
			non_void: s /= Void

	putbool (b: BOOLEAN)
			-- Write b at end of default output.
			-- Was declared in CONSOLE as synonym of put_boolean.
		require -- from IO_MEDIUM
			extendible: extendible

	putchar (c: CHARACTER_8)
			-- Write c at end of default output.
			-- Was declared in CONSOLE as synonym of put_character.
		require -- from IO_MEDIUM
			extendible: extendible

	putdouble (d: REAL_64)
			-- Write d at end of default output.
			-- Was declared in CONSOLE as synonym of put_double.
		require -- from IO_MEDIUM
			extendible: extendible

	putint (i: INTEGER_32)
			-- Write ASCII value of i at current position.
			-- Was declared in PLAIN_TEXT_FILE as synonym of put_integer and put_integer_32.
			-- (from PLAIN_TEXT_FILE)
		require -- from IO_MEDIUM
			extendible: extendible

	putreal (r: REAL_32)
			-- Write r at end of default output.
			-- Was declared in CONSOLE as synonym of put_real.
		require -- from IO_MEDIUM
			extendible: extendible

	putstring (s: STRING_8)
			-- Write s at end of default output.
			-- Was declared in CONSOLE as synonym of put_string.
		require -- from IO_MEDIUM
			extendible: extendible
			non_void: s /= Void

	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
			instance_free: class
			operating_environment_not_void: Result /= Void
	
invariant
		-- from PLAIN_TEXT_FILE
	plain_text: is_plain_text

		-- from FILE
	valid_mode: Closed_file <= mode and mode <= Append_read_file
	name_exists: internal_name /= Void
	name_not_empty: not internal_name.is_empty

		-- from FINITE
	empty_definition: Is_empty = (Count = 0)

		-- from ANY
	reflexive_equality: standard_is_equal (Current)
	reflexive_conformance: conforms_to (Current)

		-- from ACTIVE
	writable_constraint: writable implies readable
	empty_constraint: Is_empty implies (not readable) and (not writable)

		-- from BILINEAR
	not_both: not (after and before)
	before_constraint: before implies off

		-- from LINEAR
	after_constraint: after implies off

		-- from TRAVERSABLE
	empty_constraint: Is_empty implies off

note
	copyright: "Copyright (c) 1984-2018, Eiffel Software and others"
	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
	source: "[
		Eiffel Software
		5949 Hollister Ave., Goleta, CA 93117 USA
		Telephone 805-685-1006, Fax 805-685-6869
		Website http://www.eiffel.com
		Customer support http://support.eiffel.com
	]"

end -- class CONSOLE

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