
    <<HashPairCollectionsPrivate.Mesa>>
        <<Last tweaked by Mike Spreitzer on July 10, 1987 4:33:11 pm PDT>>

    DIRECTORY HashTables, Collections, PairCollections;

    HashPairCollectionsPrivate: CEDAR DEFINITIONS = {
        OPEN HT:HashTables, Collections, PairCollections;

        Ability: TYPE ~ {none, image, map};
        Abilities: TYPE ~ ARRAY Direction OF Ability;

        HashRelation: TYPE ~ REF HashRelationPrivate;
        HashRelationPrivate: TYPE ~ MONITORED RECORD [
            spaces: SpacePair,
            ability: Abilities,
            bestAbility: Ability,
            bestDir: Direction,
            tables: ARRAY Direction OF HT.HashTable,
            size: LNAT _ 0,
            freezeCount: NATURAL _ 0
            ];

        Classes: TYPE ~ ARRAY --leftToRight--Ability OF ARRAY --rightToLeft--Ability OF ARRAY Mutability OF PairCollClass;
        classes: READONLY REF Classes;

        FetchClass: PROC [ability: Abilities, mutability: Mutability] RETURNS [class: PairCollClass] ~ INLINE {RETURN 
        [classes[ability[leftToRight]][ability[rightToLeft]][mutability]]};

        }.