source: libcfa/src/enum.hfa@ e6f1a4b

#pragma once

forall(T) { // T is the based type of enum(T)
    forall(E) trait Bounded {
        E lowerBound();
        E upperBound();
    };

    forall(E| Bounded(T, E)) trait Serial {
        unsigned fromInstance(E e);
        E fromInt(unsigned i);
        E succ(E e);
        E pred(E e);
    };

    // Opague Enum + TypedEnum
    forall(E | Serial(T, E)) trait CfaEnum { 
        char * labelE(E e);
        unsigned int posE(E e);
    };

    forall(E| CfaEnum(T, E)) trait TypedEnum {
        T valueE(E e);
    };

        forall(E | TypedEnum(T, E)) {
                // comparison
                int ?==?(E l, E r);                                                             // true if l and r are same enumerators
                int ?!=?(E l, E r);                                                             // true if l and r are different enumerators
                int ?!=?(E l, zero_t);                                                  // true if l is not the first enumerator
                int ?<?(E l, E r);                                                              // true if l is an enuemerator before r
                int ?<=?(E l, E r);                                                             // true if l before or the same as r
                int ?>?(E l, E r);                                                              // true if l is an enuemrator after r
                int ?>=?(E l, E r);                                                             // true if l after or the same as r
        }
}