note
	description: "References to objects containing a character value"
	library: "Free implementation of ELKS library"
	status: "See notice at end of class."
	legal: "See notice at end of class."
	date: "$Date: 2020-06-11 19:52:41 +0000 (Thu, 11 Jun 2020) $"
	revision: "$Revision: 104466 $"

class 
	CHARACTER_8_REF

create 
	default_create

feature {NONE} -- Initialization

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

	make_from_reference (v: CHARACTER_8_REF)
			-- Initialize Current with v.item.
		require
			v_not_void: v /= Void
		do
			set_item (v.item)
		ensure
			item_set: item = v.item
		end
	
feature -- Access

	code: INTEGER_32
		obsolete "Use `natural_32_code' instead. [2017-05-31]"
			-- Associated integer value
		do
			Result := item.code
		ensure
			code_non_negatif: Result >= 0
			code_in_range: Result >= Min_value and Result <= Max_value
		end

	generating_type: TYPE [detachable CHARACTER_8_REF]
			-- Type of current object
			-- (type of which it is a direct instance)
			-- (from ANY)
		external
			"built_in"
		ensure -- from ANY
			generating_type_not_void: Result /= Void
		end

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

	hash_code: INTEGER_32
			-- Hash code value
		do
			Result := natural_32_code.hash_code
		ensure -- from HASHABLE
			good_hash_value: Result >= 0
		end

	item: CHARACTER_8
			-- Character value


	Max_ascii_value: INTEGER_32 = 127
			-- Bounds for integer representation of characters (ASCII)

	Max_value: INTEGER_32 = 255

	Min_value: INTEGER_32 = 0

	natural_32_code: NATURAL_32
			-- Associated natural value
		do
			Result := item.code.to_natural_32
		end
	
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)
		do
			if a = Void then
				Result := b = Void
			else
				Result := b /= Void and then a.is_deep_equal (b)
			end
		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)
		end

	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)
		do
			if a = Void then
				Result := b = Void
			else
				Result := b /= Void and then a.is_equal (b)
			end
		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))
		end

	frozen is_deep_equal alias "≡≡≡" (other: CHARACTER_8_REF): BOOLEAN
			-- Are Current and other attached to isomorphic object structures?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		external
			"built_in"
		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)
		end

	is_equal (other: like Current): BOOLEAN
			-- Is other attached to an object of the same type
			-- as current object and identical to it?
		require -- from ANY
			other_not_void: other /= Void
		do
			Result := other.item = item
		ensure -- from ANY
			symmetric: Result implies other ~ Current
			consistent: standard_is_equal (other) implies Result
		ensure then -- from COMPARABLE
			trichotomy: Result = (not (Current < other) and not (other < Current))
		end

	is_greater alias ">" (other: CHARACTER_8_REF): BOOLEAN
			-- Is current object greater than other?
			-- (from COMPARABLE)
		require -- from PART_COMPARABLE
			other_exists: other /= Void
		do
			Result := other < Current
		ensure then -- from COMPARABLE
			definition: Result = (other < Current)
		end

	is_greater_equal alias ">=" alias "≥" (other: CHARACTER_8_REF): BOOLEAN
			-- Is current object greater than or equal to other?
			-- (from COMPARABLE)
		require -- from PART_COMPARABLE
			other_exists: other /= Void
		do
			Result := not (Current < other)
		ensure then -- from COMPARABLE
			definition: Result = (other <= Current)
		end

	is_less alias "<" (other: like Current): BOOLEAN
			-- Is other greater than current character?
		require -- from PART_COMPARABLE
			other_exists: other /= Void
		do
			Result := natural_32_code < other.natural_32_code
		ensure then -- from COMPARABLE
			asymmetric: Result implies not (other < Current)
		ensure then
			definition: Result = (natural_32_code < other.natural_32_code)
		end

	is_less_equal alias "<=" alias "≤" (other: CHARACTER_8_REF): BOOLEAN
			-- Is current object less than or equal to other?
			-- (from COMPARABLE)
		require -- from PART_COMPARABLE
			other_exists: other /= Void
		do
			Result := not (other < Current)
		ensure then -- from COMPARABLE
			definition: Result = ((Current < other) or (Current ~ other))
		end

	max alias "∨" (other: CHARACTER_8_REF): CHARACTER_8_REF
			-- The greater of current object and other
			-- (from COMPARABLE)
		require -- from COMPARABLE
			other_exists: other /= Void
		do
			if Current >= other then
				Result := Current
			else
				Result := other
			end
		ensure -- from COMPARABLE
			current_if_not_smaller: Current >= other implies Result = Current
			other_if_smaller: Current < other implies Result = other
		end

	min alias "∧" (other: CHARACTER_8_REF): CHARACTER_8_REF
			-- The smaller of current object and other
			-- (from COMPARABLE)
		require -- from COMPARABLE
			other_exists: other /= Void
		do
			if Current <= other then
				Result := Current
			else
				Result := other
			end
		ensure -- from COMPARABLE
			current_if_not_greater: Current <= other implies Result = Current
			other_if_greater: Current > other implies Result = other
		end

	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)
		do
			if a = Void then
				Result := b = Void
			else
				Result := b /= Void and then a.standard_is_equal (b)
			end
		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))
		end

	frozen standard_is_equal alias "≜" (other: CHARACTER_8_REF): 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
		external
			"built_in"
		ensure -- from ANY
			same_type: Result implies same_type (other)
			symmetric: Result implies other.standard_is_equal (Current)
		end

	three_way_comparison alias "⋚" (other: CHARACTER_8_REF): INTEGER_32
			-- If current object equal to other, 0;
			-- if smaller, -1; if greater, 1
			-- (from COMPARABLE)
		require -- from COMPARABLE
			other_exists: other /= Void
		do
			if Current < other then
				Result := -1
			elseif other < Current then
				Result := 1
			end
		ensure -- from COMPARABLE
			equal_zero: (Result = 0) = (Current ~ other)
			smaller_negative: (Result = -1) = (Current < other)
			greater_positive: (Result = 1) = (Current > other)
		end
	
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
		external
			"built_in"
		end

	is_alpha: BOOLEAN
			-- Is item alphabetic?
			-- Alphabetic is is_upper or is_lower
		do
			Result := (character_types (item.code) & (Is_upper_flag | Is_lower_flag)) > 0
		end

	is_alpha_numeric: BOOLEAN
			-- Is item alphabetic or a digit?
		do
			Result := (character_types (item.code) & (Is_upper_flag | Is_lower_flag | Is_digit_flag)) > 0
		end

	is_control: BOOLEAN
			-- Is item a control character?
		do
			Result := (character_types (item.code) & Is_control_flag) > 0
		end

	is_digit: BOOLEAN
			-- Is item a digit?
			-- A digit is one of 0123456789
		do
			Result := (character_types (item.code) & Is_digit_flag) > 0
		end

	is_graph: BOOLEAN
			-- Is item a printable character except space?
		do
			Result := (character_types (item.code) & (Is_upper_flag | Is_lower_flag | Is_digit_flag | Is_punctuation_flag)) > 0
		end

	is_hashable: BOOLEAN
			-- May current object be hashed?
			-- (True by default.)
			-- (from HASHABLE)
		do
			Result := True
		end

	is_hexa_digit: BOOLEAN
			-- Is item an hexadecimal digit?
			-- A digit is one of 0123456789ABCDEFabcedf
		do
			Result := (character_types (item.code) & (Is_hexa_digit_flag | Is_digit_flag)) > 0
		end

	is_lower: BOOLEAN
			-- Is item lowercase?
		do
			Result := (character_types (item.code) & Is_lower_flag) > 0
		end

	is_printable: BOOLEAN
			-- Is item a printable character including space?
		do
			Result := (character_types (item.code) & (Is_upper_flag | Is_lower_flag | Is_digit_flag | Is_punctuation_flag | Is_space_flag)) > 0
		end

	is_punctuation: BOOLEAN
			-- Is item a punctuation?
		do
			Result := (character_types (item.code) & Is_punctuation_flag) > 0
		end

	is_space: BOOLEAN
			-- Is item a white space?
		do
			Result := (character_types (item.code) & Is_white_space_flag) > 0
		end

	is_upper: BOOLEAN
			-- Is item uppercase?
		do
			Result := (character_types (item.code) & Is_upper_flag) > 0
		end

	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
		external
			"built_in"
		ensure -- from ANY
			definition: Result = (conforms_to (other) and other.conforms_to (Current))
		end
	
feature -- Element change

	set_item (c: CHARACTER_8)
			-- Make c the item value.
		do
			item := c
		end
	
feature -- Conversion

	as_lower: CHARACTER_8
			-- Lowercase value of item
			-- Returns item if not is_upper
			-- Was declared in CHARACTER_8_REF as synonym of lower.
		do
			Result := Lower_value [natural_32_code.as_integer_32]
		end

	as_upper: CHARACTER_8
			-- Uppercase value of item.
			-- Returns item if not is_lower.
			-- Caveat: not all upper-case values fit into CHARACTER_8. Use CHARACTER_32 instead.
			-- Was declared in CHARACTER_8_REF as synonym of upper.
		do
			Result := Upper_value [natural_32_code.as_integer_32]
		end

	lower: CHARACTER_8
			-- Lowercase value of item
			-- Returns item if not is_upper
			-- Was declared in CHARACTER_8_REF as synonym of as_lower.
		do
			Result := Lower_value [natural_32_code.as_integer_32]
		end

	to_character_32: CHARACTER_32
			-- Associated character in 32 bit version
		do
			Result := item.to_character_32
		end

	to_character_8: CHARACTER_8
			-- Associated character in 8 bit version
		do
			Result := item
		end

	to_reference: CHARACTER_8_REF
			-- Associated reference of Current
		do
			create Result;
			Result.set_item (item)
		ensure
			to_reference_not_void: Result /= Void
		end

	upper: CHARACTER_8
			-- Uppercase value of item.
			-- Returns item if not is_lower.
			-- Caveat: not all upper-case values fit into CHARACTER_8. Use CHARACTER_32 instead.
			-- Was declared in CHARACTER_8_REF as synonym of as_upper.
		do
			Result := Upper_value [natural_32_code.as_integer_32]
		end
	
feature -- Duplication

	frozen clone (other: detachable ANY): like other
		obsolete "Use `twin' instead. [2017-05-31]"
			-- Void if other is void; otherwise new object
			-- equal to other
			--
			-- For non-void other, clone calls copy;
			-- to change copying/cloning semantics, redefine copy.
			-- (from ANY)
		do
			if other /= Void then
				Result := other.twin
			end
		ensure -- from ANY
			instance_free: class
			equal: Result ~ other
		end

	copy (other: CHARACTER_8_REF)
			-- 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)
		external
			"built_in"
		ensure -- from ANY
			is_equal: Current ~ other
		end

	frozen deep_clone (other: detachable ANY): like other
		obsolete "Use `deep_twin' instead. [2017-05-31]"
			-- Void if other is void: otherwise, new object structure
			-- recursively duplicated from the one attached to other
			-- (from ANY)
		do
			if other /= Void then
				Result := other.deep_twin
			end
		ensure -- from ANY
			instance_free: class
			deep_equal: deep_equal (other, Result)
		end

	frozen deep_copy (other: CHARACTER_8_REF)
			-- Effect equivalent to that of:
			--		copy (other . deep_twin)
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		do
			copy (other.deep_twin)
		ensure -- from ANY
			deep_equal: deep_equal (Current, other)
		end

	frozen deep_twin: CHARACTER_8_REF
			-- New object structure recursively duplicated from Current.
			-- (from ANY)
		external
			"built_in"
		ensure -- from ANY
			deep_twin_not_void: Result /= Void
			deep_equal: deep_equal (Current, Result)
		end

	frozen standard_clone (other: detachable ANY): like other
		obsolete "Use `standard_twin' instead. [2017-05-31]"
			-- Void if other is void; otherwise new object
			-- field-by-field identical to other.
			-- Always uses default copying semantics.
			-- (from ANY)
		do
			if other /= Void then
				Result := other.standard_twin
			end
		ensure -- from ANY
			instance_free: class
			equal: standard_equal (Result, other)
		end

	frozen standard_copy (other: CHARACTER_8_REF)
			-- 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)
		external
			"built_in"
		ensure -- from ANY
			is_standard_equal: standard_is_equal (other)
		end

	frozen standard_twin: CHARACTER_8_REF
			-- New object field-by-field identical to other.
			-- Always uses default copying semantics.
			-- (from ANY)
		external
			"built_in"
		ensure -- from ANY
			standard_twin_not_void: Result /= Void
			equal: standard_equal (Result, Current)
		end

	frozen twin: CHARACTER_8_REF
			-- New object equal to Current
			-- twin calls copy; to change copying/twinning semantics, redefine copy.
			-- (from ANY)
		external
			"built_in"
		ensure -- from ANY
			twin_not_void: Result /= Void
			is_equal: Result ~ Current
		end
	
feature -- Basic operations

	frozen as_attached: attached CHARACTER_8_REF
		obsolete "Remove calls to this feature. [2017-05-31]"
			-- Attached version of Current.
			-- (Can be used during transitional period to convert
			-- non-void-safe classes to void-safe ones.)
			-- (from ANY)
		do
			Result := Current
		end

	frozen default: detachable CHARACTER_8_REF
			-- Default value of object's type
			-- (from ANY)
		do
		end

	frozen default_pointer: POINTER
			-- Default value of type POINTER
			-- (Avoid the need to write p.default for
			-- some p of type POINTER.)
			-- (from ANY)
		do
		ensure -- from ANY
			instance_free: class
		end

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

	frozen do_nothing
			-- Execute a null action.
			-- (from ANY)
		do
		ensure -- from ANY
			instance_free: class
		end
	
feature {NONE} -- Implementation

	character_types (a_code: INTEGER_32): NATURAL_8
			-- Associated type for character of code a_code
		do
			if a_code < 256 then
				Result := Internal_character_types.item (a_code)
			end
		end

	Internal_character_types: SPECIAL [NATURAL_8]
			-- Array which stores the various type for the ASCII characters
		once
			create Result.make_empty (256);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag | Is_white_space_flag);
			Result.extend (Is_control_flag | Is_white_space_flag);
			Result.extend (Is_control_flag | Is_white_space_flag);
			Result.extend (Is_control_flag | Is_white_space_flag);
			Result.extend (Is_control_flag | Is_white_space_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_white_space_flag | Is_space_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_digit_flag);
			Result.extend (Is_digit_flag);
			Result.extend (Is_digit_flag);
			Result.extend (Is_digit_flag);
			Result.extend (Is_digit_flag);
			Result.extend (Is_digit_flag);
			Result.extend (Is_digit_flag);
			Result.extend (Is_digit_flag);
			Result.extend (Is_digit_flag);
			Result.extend (Is_digit_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_upper_flag | Is_hexa_digit_flag);
			Result.extend (Is_upper_flag | Is_hexa_digit_flag);
			Result.extend (Is_upper_flag | Is_hexa_digit_flag);
			Result.extend (Is_upper_flag | Is_hexa_digit_flag);
			Result.extend (Is_upper_flag | Is_hexa_digit_flag);
			Result.extend (Is_upper_flag | Is_hexa_digit_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_lower_flag | Is_hexa_digit_flag);
			Result.extend (Is_lower_flag | Is_hexa_digit_flag);
			Result.extend (Is_lower_flag | Is_hexa_digit_flag);
			Result.extend (Is_lower_flag | Is_hexa_digit_flag);
			Result.extend (Is_lower_flag | Is_hexa_digit_flag);
			Result.extend (Is_lower_flag | Is_hexa_digit_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag | Is_space_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_control_flag);
			Result.extend (Is_space_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (0);
			Result.extend (0);
			Result.extend (0);
			Result.extend (0);
			Result.extend (0);
			Result.extend (Is_punctuation_flag);
			Result.extend (0);
			Result.extend (0);
			Result.extend (0);
			Result.extend (Is_punctuation_flag);
			Result.extend (0);
			Result.extend (0);
			Result.extend (0);
			Result.extend (0);
			Result.extend (0);
			Result.extend (0);
			Result.extend (0);
			Result.extend (0);
			Result.extend (0);
			Result.extend (Is_lower_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_punctuation_flag);
			Result.extend (0);
			Result.extend (0);
			Result.extend (0);
			Result.extend (Is_punctuation_flag);
			Result.extend (0);
			Result.extend (0);
			Result.extend (0);
			Result.extend (Is_punctuation_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (0);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_upper_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (0);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag);
			Result.extend (Is_lower_flag)
		ensure
			internal_character_types_not_void: Result /= Void
		end

	Is_control_flag: NATURAL_8 = 32

	Is_digit_flag: NATURAL_8 = 4

	Is_hexa_digit_flag: NATURAL_8 = 64

	Is_lower_flag: NATURAL_8 = 2

	Is_punctuation_flag: NATURAL_8 = 16

	Is_space_flag: NATURAL_8 = 128

	Is_upper_flag: NATURAL_8 = 1

	Is_white_space_flag: NATURAL_8 = 8

	Lower_value: SPECIAL [CHARACTER_8]
			-- Lower value indexed by code point.
		once
			Result := ("%U%/1/%/2/%/3/%/4/%/5/%/6/%/7/%B%T%N%/11/%F%R%/14/%/15/%/16/%/17/%/18/%/19/%/20/%/21/%/22/%/23/%/24/%/25/%/26/%/27/%/28/%/29/%/30/%/31/ !%"#$%%&'()*+,-./0123456789:;<=>?@abcdefghijklmnopqrstuvwxyz[\]^_`abcdefghijklmnopqrstuvwxyz{|}~%/127/%/128/%/129/%/130/%/131/%/132/%/133/%/134/%/135/%/136/%/137/%/138/%/139/%/140/%/141/%/142/%/143/%/144/%/145/%/146/%/147/%/148/%/149/%/150/%/151/%/152/%/153/%/154/%/155/%/156/%/157/%/158/%/159/ ¡¢£¤¥¦§¨©ª«¬­®¯°±²³´µ¶·¸¹º»¼½¾¿àáâãäåæçèéêëìíîïðñòóôõö×øùúûüýþßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþÿ").area
		end

	Upper_value: SPECIAL [CHARACTER_8]
			-- Upper value indexed by code point.
		once
			Result := ("%U%/1/%/2/%/3/%/4/%/5/%/6/%/7/%B%T%N%/11/%F%R%/14/%/15/%/16/%/17/%/18/%/19/%/20/%/21/%/22/%/23/%/24/%/25/%/26/%/27/%/28/%/29/%/30/%/31/ !%"#$%%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`ABCDEFGHIJKLMNOPQRSTUVWXYZ{|}~%/127/%/128/%/129/%/130/%/131/%/132/%/133/%/134/%/135/%/136/%/137/%/138/%/139/%/140/%/141/%/142/%/143/%/144/%/145/%/146/%/147/%/148/%/149/%/150/%/151/%/152/%/153/%/154/%/155/%/156/%/157/%/158/%/159/ ¡¢£¤¥¦§¨©ª«¬­®¯°±²³´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ÷ØÙÚÛÜÝÞÿ").area
		end
	
feature -- Basic routines

	difference alias "|-|" (other: CHARACTER_8): INTEGER_32
			-- Difference between the codes of item and other
		do
			Result := item.code - other.code
		ensure
			valid_result: other + Result = item
		end

	minus alias "-" alias "−" (decr: INTEGER_32): CHARACTER_8
			-- Subtract decr from the code of item
		require
			valid_decrement: (item.code - decr).is_valid_character_8_code
		do
			Result := (item.code - decr).to_character_8
		ensure
			valid_result: item |-| Result = decr
		end

	next: CHARACTER_8
			-- Next character
		require
			valid_character: (item.code + 1).is_valid_character_8_code
		do
			Result := item + 1
		ensure
			valid_result: Result |-| item = 1
		end

	plus alias "+" (incr: INTEGER_32): CHARACTER_8
			-- Add incr to the code of item
		require
			valid_increment: (item.code + incr).is_valid_character_8_code
		do
			Result := (item.code + incr).to_character_8
		ensure
			valid_result: Result |-| item = incr
		end

	previous: CHARACTER_8
			-- Previous character
		require
			valid_character: (item.code - 1).is_valid_character_8_code
		do
			Result := item - 1
		ensure
			valid_result: Result |-| item = -1
		end
	
feature -- Output

	Io: STD_FILES
			-- Handle to standard file setup
			-- (from ANY)
		once
			create Result;
			Result.set_output_default
		ensure -- from ANY
			instance_free: class
			io_not_void: Result /= Void
		end

	out: STRING_8
			-- Printable representation of character
		do
			create Result.make (1);
			Result.append_character (item)
		ensure -- from ANY
			out_not_void: Result /= Void
		end

	print (o: detachable ANY)
			-- Write terse external representation of o
			-- on standard output.
			-- (from ANY)
		local
			s: READABLE_STRING_8
		do
			if attached o then
				s := o.out
				if attached {READABLE_STRING_32} s as s32 then
					Io.put_string_32 (s32)
				elseif attached {READABLE_STRING_8} s as s8 then
					Io.put_string (s8)
				else
					Io.put_string_32 (s.as_string_32)
				end
			end
		ensure -- from ANY
			instance_free: class
		end

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

	Operating_environment: OPERATING_ENVIRONMENT
			-- Objects available from the operating system
			-- (from ANY)
		once
			create Result
		ensure -- from ANY
			instance_free: class
			operating_environment_not_void: Result /= Void
		end
	
feature {NONE} -- Retrieval

	frozen internal_correct_mismatch
			-- Called from runtime to perform a proper dynamic dispatch on correct_mismatch
			-- from MISMATCH_CORRECTOR.
			-- (from ANY)
		local
			l_msg: STRING_32
			l_exc: EXCEPTIONS
		do
			if attached {MISMATCH_CORRECTOR} Current as l_corrector then
				l_corrector.correct_mismatch
			else
				create l_msg.make_from_string ("Mismatch: ".as_string_32)
				create l_exc;
				l_msg.append (generating_type.name_32);
				l_exc.raise_retrieval_exception (l_msg)
			end
		end
	
invariant
		-- from COMPARABLE
	irreflexive_comparison: not (Current < Current)

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

note
	copyright: "Copyright (c) 1984-2020, 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 CHARACTER_8_REF

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