Class CHARACTER

5.7 Class CHARACTER

indexing

description: "Characters, with comparison operations and an ASCII code"

expanded class interface

CHARACTER

feature -- Access

code: INTEGER
        -- Associated integer value

hash_code: INTEGER
        -- Hash code value
        -- (From HASHABLE.)
    ensure
        good_hash_value: Result >= 0

feature -- Comparison

infix "<" (other: like Current): BOOLEAN
        -- Is other greater than current character?
        -- (From COMPARABLE.)
    require
        other_exists: other /= Void
    ensure
        asymmetric: Result implies not (other < Current)

infix "<=" (other: like Current): BOOLEAN
        -- Is current character less than or equal to other?
        -- (From COMPARABLE.)
    require
        other_exists: other /= Void
    ensure
        definition: Result = (Current < other) or is_equal (other);

infix ">=" (other: like Current): BOOLEAN
        -- Is current object greater than or equal to other?
        -- (From COMPARABLE.)
    require
        other_exists: other /= Void
    ensure
        definition: Result = (other <= Current)

infix ">" (other: like Current): BOOLEAN
        -- Is current object greater than other?
        -- (From COMPARABLE.)
    require
        other_exists: other /= Void
    ensure
        definition: Result = (other < Current)

max (other: like Current): like Current
        -- The greater of current object and other
        -- (From COMPARABLE.)
    require
        other_exists: other /= Void
    ensure
        current_if_not_smaller: (Current >= other) implies (Result = Current)
        other_if_smaller: (Current < other) implies (Result = other)

min (other: like Current): like Current
        -- The smaller of current object and other
        -- (From COMPARABLE.)
    require
        other_exists: other /= Void
    ensure
        current_if_not_greater: (Current <= other) implies (Result = Current)
        other_if_greater: (Current > other) implies (Result = other)

three_way_comparison (other: like Current): INTEGER
        -- If current object equal to other, 0; if smaller,
        -- -1; if greater, 1.
        -- (From COMPARABLE.)
    require
        other_exists: other /= Void
    ensure
        equal_zero: (Result = 0) = is_equal (other);
        smaller: (Result = -1) = Current < other;
        greater_positive: (Result = 1) = Current > other

feature -- Output

out: STRING
        -- Printable representation of character
        -- (From GENERAL.)

invariant

irreflexive_comparison: not (Current < Current)

end