EiffelBase class
(HTML page generated by ISE Eiffel 4.2)
Eiffel Class
indexing
description: "References to objects containing a character value";
status: "See notice at end of class";
date: "$Date: 2007-03-30 11:10:11 -0800 (Fri, 30 Mar 2007) $";
revision: "$Revision: 95354 $"
class CHARACTER_REF
inherit
COMPARABLE
rename
max as max_ref,
min as min_ref
export
{NONE} max_ref, min_ref
redefine
out, three_way_comparison, is_equal
end;
HASHABLE
redefine
is_hashable, out, is_equal
end
feature -- Access
item: CHARACTER;
-- Character value
code: INTEGER is
-- Associated integer value
do
Result := chcode (item)
end;
hash_code: INTEGER is
-- Hash code value
do
Result := code
end;
feature -- Status report
is_hashable: BOOLEAN is
-- May current object be hashed?
-- (True if it is not its type's default.)
do
Result := item /= '%U'
end;
feature -- Comparison
infix "<" (other: like Current): BOOLEAN is
-- Is other greater than current character?
do
Result := item < other.item
end;
is_equal (other: like Current): BOOLEAN is
-- Is other attached to an object of the same type
-- as current object and identical to it?
do
Result := other.item = item
end;
three_way_comparison (other: CHARACTER_REF): INTEGER is
-- If current object equal to other, 0;
-- if smaller, -1; if greater, 1
do
if item < other.item then
Result := -1
elseif other.item < item then
Result := 1
end
end;
max (other: CHARACTER_REF): CHARACTER is
-- The greater of current object and other
require
other_exists: other /= void
do
Result := max_ref (other).item
end;
min (other: CHARACTER_REF): CHARACTER is
-- The smaller of current object and other
require
other_exists: other /= void
do
Result := min_ref (other).item
end;
feature -- Basic routines
infix "+" (incr: INTEGER): CHARACTER is
-- Add incr to the code of item
require
valid_upper_increment: item.code + incr <= 255;
valid_lower_increment: item.code + incr >= 0
do
Result := chconv (chcode (item) + incr)
ensure
valid_result: Result |-| item = incr
end;
infix "-" (decr: INTEGER): CHARACTER is
-- Subtract decr to the code of item
require
valid_upper_decrement: item.code - decr <= 255;
valid_lower_decrement: item.code - decr >= 0
do
Result := chconv (chcode (item) - decr)
ensure
valid_result: item |-| Result = decr
end;
infix "|-|" (other: CHARACTER): INTEGER is
-- Difference between the codes of item and other
do
Result := chcode (item) - chcode (other)
ensure
valid_result: other + Result = item
end;
next: CHARACTER is
-- Next character
require
valid_character: item /= '%/255/'
do
Result := item + 1
ensure
valid_result: Result |-| item = 1
end;
previous: CHARACTER is
-- Previous character
require
valid_character: item /= '%U'
do
Result := item - 1
ensure
valid_result: Result |-| item = -1
end;
feature -- Element change
set_item (c: CHARACTER) is
-- Make c the item value.
do
item := c
end;
feature -- Output
out: STRING is
-- Printable representation of character
do
Result := c_outc (item)
end;
feature -- Conversion
upper: CHARACTER is
-- Uppercase value of item
-- Returns item if not is_lower
do
Result := chupper (item)
end;
lower: CHARACTER is
-- Lowercase value of item
-- Returns item if not is_upper
do
Result := chlower (item)
end;
feature -- Status report
is_lower: BOOLEAN is
-- Is item lowercase?
do
Result := chis_lower (item)
end;
is_upper: BOOLEAN is
-- Is item uppercase?
do
Result := chis_upper (item)
end;
is_digit: BOOLEAN is
-- Is item a digit?
-- A digit is one of 0123456789
do
Result := chis_digit (item)
end;
is_alpha: BOOLEAN is
-- Is item alphabetic?
-- Alphabetic is is_upper or is_lower
do
Result := chis_alpha (item)
end;
feature {NONE} -- Implementation
chcode (c: like item): INTEGER is
-- Associated integer value
external
"C | %"eif_misc.h%""
end;
chconv (i: INTEGER): CHARACTER is
-- Character associated with integer value i
external
"C | %"eif_misc.h%""
end;
c_outc (c: CHARACTER): STRING is
-- Printable representation of character
external
"C | %"eif_out.h%""
end;
chupper (c: CHARACTER): CHARACTER is
external
"C | %"eif_misc.h%""
end;
chlower (c: CHARACTER): CHARACTER is
external
"C | %"eif_misc.h%""
end;
chis_lower (c: CHARACTER): BOOLEAN is
external
"C | %"eif_misc.h%""
end;
chis_upper (c: CHARACTER): BOOLEAN is
external
"C | %"eif_misc.h%""
end;
chis_digit (c: CHARACTER): BOOLEAN is
external
"C | %"eif_misc.h%""
end;
chis_alpha (c: CHARACTER): BOOLEAN is
external
"C | %"eif_misc.h%""
end;
end -- class CHARACTER_REF
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