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joseoliv/RestrictTo

Last active Apr 24, 2021
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restrict the values a variable can hold
package metaobjectTest
@doc{*
Annotation 'type' should be attached to a type. It checks whether
the value of the type obeys the expression that is attached to
the annotation. Use 'self' as the value of the object that is
being restricted. Therefore, the expressions can be something like:
self >= 0
self >= 0 && self < 5
self[0] == 'a'
*}
object RestrictTo
func run {
var Int@restrictTo{* self >= 0 *} age;
age = 0;
age = 10;
var ok = false;
{
age = -1;
} catch: { (: CyException e :)
ok = true
};
assert ok;
var String@restrictTo{* self[0] == 'a' *} s;
s = "abc";
ok = false;
{
s = "bca";
"error !" println;
} catch: { (: CyException e :)
ok = true
};
assert ok;
}
end
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