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restrict the values a variable can hold
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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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