Coercion

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SYNTAX:
coercion_decl = '{' ( entity_ref | type_ref ) '}' .
Coercion can be used in NEW and assignment statements to specify which particular instance type to create, in case that this is not uniquely defined by the domain type of the attribute. This is the case when the actual attribute domain is a supertype entity or a SELECT type.
Another case is when a global or local variable is of type GENERIC or of a supertype entity. Then coercion must be used in case an instance should be explicitly created, by the NEW statement, or implicitly created, by the assignment statement.
Coercion can in a similar way be used to define the specific aggregate type for an attribute, local variable or global variable that is of a SELECT type.