VDM-10 Language Manual

VDM-10 Language Manual
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Domain : map nat to nat | seq of (nat*nat) -> set of nat
Domain(m) ==
if is_(m, map nat to nat)
then dom m
else {d | mk_(d,-) in set elems m}
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In addition there are examples on page 27.
6.18 Base Class Membership (VDM++ and VDM-RT)
Syntax: expression = . . .
| isofbaseclass expression
| . . . ;
isofbaseclass expression = ‘isofbaseclass’, ‘(’, name, expression, ‘)’ ;
Semantic: The function isofbaseclass when applied to an object reference expression
and a class name name yields the boolean value true if and only if name is a root superclass
in the inheritance chain of the object referenced to by expression, and false otherwise.
Examples: Suppose that BinarySearchTree is a subclass of Tree, Tree is not a subclass of
any other class and Queue is not related by inheritance to either Tree or BinarySearchTree.
Let t be an instance of textttTree, b is an instance of BinarySearchTree and q is an
instance of Queue. Then:
isofbaseclass(Tree, t) ≡ true
isofbaseclass(BinarySearchTree, b) ≡ false
isofbaseclass(Queue, q) ≡ true
isofbaseclass(Tree, b) ≡ true
isofbaseclass(Tree, q) ≡ false
6.19 Class Membership
Syntax expression = . . .
| isofclass expression
| . . . ;
isofclass expression = ‘isofclass’, ‘(’, name, expression, ‘)’ ;
Semantics: The function isofclass when applied to an object reference expression and a class
name name yields the boolean value true if and only if expression refers to an object of
class name or to an object of any of the subclasses of name, and false otherwise.
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