source: doc/theses/jiada_liang_MMath/user_define_enum.cfa@ 931f1b4

#include <fstream.hfa>
#include <enum.hfa>
#include <string.hfa>

forall( E, V | TypedEnum( E, V ) | { string str( V ); } ) // routine to format value}$
string format_enum( E e ) {
        return label( e ) + '(' + str( value( e ) ) + ')'; // "label( value )"
}
enum(size_t) RGB { Red = 0xFF0000, Green = 0x00FF00, Blue = 0x0000FF };
// string library has conversion from size_t to string

struct color_code { int R, G, B; };
enum(color_code) Rainbow {
        Red = {255, 0, 0}, Orange = {255, 127, 0}, Yellow = {255, 255, 0}, Green = {0, 255, 0}, // ...
};
string str( color_code cc ) with( cc ) {
        return str( R ) + ',' + str( G ) + ',' + str( B ); // "R,G,B"
}

enum Fruit { Apple, Banana, Cherry };                                   // C enum
const char * label( Fruit f ) {
        static const char * labels[] = { "Apple", "Banana", "Cherry" };
        return labels[f];
}
int posn( Fruit f ) { return f; }
int value( Fruit f ) {
        static const char values[] = { 'a', 'b', 'c' };
        return values[f];
}
string str( int f ) {
        string s = (char)f;
        return s;
}
int main() {
        sout | format_enum( RGB.Green );                                        // "Green(65280)"}$
        sout | format_enum( Rainbow.Green );                            // "Green(0,255,0)"}$
        sout | format_enum( Cherry );                                           // "Cherry(c)"
}