Ticket #1770: boolean.pmc

/* Copyright (c) 2010, Parrot Foundation.
$Id$

=head1 NAME

src/pmc/boolean.pmc - Boolean PMC

=head1 DESCRIPTION

This PMC implements a Boolean type with a single true/false value.
A C<Boolean> does not morph to other types when its value is set; it simply
changes its value.

This implementation of C<Boolean> inherits from the C<Scalar> PMC.
Unlike the previous implementation, it does I<not> inherit
from C<Integer>.

=head2 Functions

=over

=cut

*/

/* This new Boolean PMC stores its boolean value in a private PObj flag. */

#define boolean_FLAG PObj_private0_FLAG

#define get_boolean_FLAG(pmc) \
    ((PObj_get_FLAGS(pmc) & boolean_FLAG) != 0)

#define set_boolean_FLAG(pmc, val) \
     if (val) \
         PObj_get_FLAGS(pmc) |= boolean_FLAG; \
     else \
         PObj_get_FLAGS(pmc) &= ~boolean_FLAG;

#define flip_boolean_FLAG(pmc) \
     PObj_get_FLAGS(pmc) ^= boolean_FLAG


pmclass Boolean extends scalar provides boolean provides scalar manual_attrs {

/*

=item C<void init()>

Create a new C<Boolean> with initial value C<FALSE>.

=item C<void init_pmc(PMC *value)>

Create a new C<Boolean> with the given initial value interpreted
as a Boolean.

=cut

*/

    /* These two init functions set the boolean flag directly. */

    VTABLE void init () {
        set_boolean_FLAG(SELF, FALSE);
    }

    VTABLE void init_pmc (PMC *value) {
        INTVAL v = PMC_IS_NULL(value) ? FALSE : VTABLE_get_bool(INTERP, value);
        set_boolean_FLAG(SELF, v);
    }

/*

=item C<INTVAL get_bool()>

Obtain the value of the C<Boolean> as an integer: 1 = C<TRUE>, 0 = C<FALSE>.

=item C<INTVAL get_integer()>

Same as C<get_bool()>.

=item C<FLOATVAL get_number()>

Obtain the value of the C<Boolean> as a float: 1.0 = C<TRUE>, 0.0 = C<FALSE>.

=item C<STRING *get_string()>

Obtain the value of the C<Boolean> as a string: "1" = C<TRUE>, "0" = C<FALSE>.

=cut

*/

    VTABLE INTVAL get_bool () {
        return get_boolean_FLAG(SELF);
    }

    VTABLE INTVAL get_integer () {
        return SELF.get_bool();
    }      

    VTABLE FLOATVAL get_number () {
        INTVAL value = SELF.get_bool();
        return (FLOATVAL)value;
    }      

    VTABLE STRING *get_string () {
        return Parrot_str_from_int(INTERP, SELF.get_integer());
    }

/*

=item C<void set_bool(INTVAL value)>

Sets the value of the Boolean to the specified integer value: 0 = C<FALSE>, non-0 =
C<TRUE>.

=item C<void set_integer_native(INTVAL value)>

Same as C<set_bool()>.

=item C<void set_number_native(FLOATVAL value)>

Sets the value of the Boolean to the specified float value: 0.0 = C<FALSE>, non-0.0 =
C<TRUE>.

=item C<void set_string_native(STRING *value)>

Sets the Boolean to the value represented by the specified string. All values are
considered C<TRUE> except for C<""> and C<"0>", which are considered
C<FALSE>.

=cut

*/

    VTABLE void set_bool (INTVAL value) {
        set_boolean_FLAG(SELF, value);
    }

    VTABLE void set_integer_native (INTVAL value) {
        SELF.set_bool(value);
    }

    VTABLE void set_number_native (FLOATVAL value) {
        SELF.set_bool(!FLOAT_IS_ZERO(value));
    }

    VTABLE void set_string_native (STRING *value) {
        SELF.set_bool(Parrot_str_boolean(INTERP, value));
    }

/**    VTABLE PMC *neg (PMC *dest) {
        dest = Parrot_pmc_new_init_int(INTERP, VTABLE_type(INTERP, SELF),
                                       SELF.get_bool());
        return dest;
    }

    VTABLE void i_neg () {
        /* Nothing to do for an in-place negate.
    }**/

    /* No POD documentation, since the reader should see Scalar. */

    VTABLE void i_logical_not () {
        flip_boolean_FLAG(SELF);
    }

/*

=item C<void freeze(PMC *info)>

Used to archive the C<Boolean>.

=item C<void thaw(PMC *info)>

Used to unarchive the C<Boolean>.

=cut

*/

    VTABLE void freeze (PMC *info) {
        SUPER(info);
        VTABLE_push_integer(INTERP, info, SELF.get_bool());
    }

    VTABLE void thaw (PMC *info) {
        SUPER(info);
        SELF.set_bool(VTABLE_shift_integer(INTERP, info));
    }

}

/*

=back

See also the C<Scalar> PMC.

=cut

*/

/* Local variables:
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