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    Types: TextFile
    Names: »B«

└─⟦a7d1ea751⟧ Bits:30000550 8mm tape, Rational 1000, !users!projects 94_04_11
    └─ ⟦129cab021⟧ »DATA« 
        └─⟦this⟧ 

TextFile

separate (Generic_Predicate)
package body Primary_Predicate is
    function Make_Alias_Definition (The_Alias : Alias.Name) return Object is
    begin
        return Object'(Kind => Alias_Definition, The_Alias => The_Alias);
    end Make_Alias_Definition;


    function Make_Conjunction
                (Left, Right : Generic_Predicate.Object) return Object is
    begin
        return Object'(Kind                => Predicate_Conjunction,
                       The_Left_Predicate  => Left,
                       The_Right_Predicate => Right);
    end Make_Conjunction;


    function Make_Collection
                (Of_Objects : Generic_Predicate.Objects) return Object is
    begin
        return Object'(Kind           => Predicate_Collection,
                       The_Collection =>
                          new Generic_Predicate.Objects'(Of_Objects));
    end Make_Collection;


    function Get_Collection (From_Object : Object)
                            return Generic_Predicate.Objects is
    begin
        return From_Object.The_Collection.all;
    end Get_Collection;


    procedure Put (The_Object : Object; Where : Output_Stream.Object) is
        use Output_Stream;
    begin
        case The_Object.Kind is
            when Alias_Definition =>
                Put ("Define_As(", Where);
                Alias.Put (The_Object.The_Alias, Where);
                Put (")", Where);
            when Predicate_Conjunction =>
                Put (The_Object.The_Left_Predicate, Where);
                Put (" and ", Where);
                Put (The_Object.The_Right_Predicate, Where);
            when Predicate_Collection =>
                Put ("Collection of predicates", Where);
        end case;
    end Put;


    function Match (Value : Slot.Object; Against : Object) return Boolean is
    begin  
        case Against.Kind is
            when Alias_Definition =>
                Alias.Set (Against.The_Alias, To => Value);
                return True;
            when Predicate_Conjunction =>
                return Match (Value, Against.The_Left_Predicate) and then
                          Match (Value, Against.The_Right_Predicate);
            when Predicate_Collection =>
                return False;
        end case;
    end Match;
end Primary_Predicate;