Invercargill/src/lib/Operators/Stringify.vala

namespace Invercargill.Operators {

    /**
     * Default stringify function for a generic type.
     *
     * Marshalling, same as hash()/equality()/comparison():
     *  - inline types (bool, char/uchar, int/uint, long/ulong, enums)
     *    arrive as a pointer-sized integer carrying the value itself.
     *  - always-boxed types (int64, uint64, float, double and nullable
     *    forms) arrive as pointers to the boxed payloads and are
     *    dereferenced (a null box stringifies as "null").
     *
     * char stringifies as the character, not its numeric code (typeof
     * (char) == typeof(int8), so this branch must come first and serves
     * both). uchar stringifies numerically, matching uint8. Enums
     * stringify as their value nick when registered, falling back to
     * the numeric value.
     *
     * Note: typeof(T) cannot distinguish T=int from T=int? (same GType);
     * inline branches serve the non-nullable forms.
     */
    public static StringifyDelegate<T> stringify<T>() {
        var type = typeof(T);
        if(type == typeof(string)) { return i => (string)i; }
        else if(type == typeof(char)) { return i => ((char)i).to_string(); }
        else if(type == typeof(int)) { return i => ((int)i).to_string(); }
        else if(type == typeof(uint8)) { return i => ((uint8)i).to_string(); }
        else if(type == typeof(int16)) { return i => ((int16)i).to_string(); }
        else if(type == typeof(uint16)) { return i => ((uint16)i).to_string(); }
        else if(type == typeof(uint)) { return i => ((uint)i).to_string(); }
        else if(type == typeof(int64)) { return i => ((int64?)i) == null ? "null" : ((int64)((int64?)i)).to_string(); }
        else if(type == typeof(uint64)) { return i => ((uint64?)i) == null ? "null" : ((uint64)((uint64?)i)).to_string(); }
        else if(type == typeof(double)) { return i => ((double?)i) == null ? "null" : ((double)((double?)i)).to_string(); }
        else if(type == typeof(float)) { return i => ((float?)i) == null ? "null" : ((float)((float?)i)).to_string(); }
        else if(type == typeof(long)) { return i => ((long)i).to_string(); }
        else if(type == typeof(ulong)) { return i => ((ulong)i).to_string(); }
        else if(type == typeof(bool)) { return i => ((bool)i).to_string(); }
        else if(type.is_enum()) {
            var enum_class = (EnumClass)type.class_ref();
            return i => { var v = enum_class.get_value((int)i); return v == null ? ((int)i).to_string() : v.value_nick; };
        }
        else if(type.is_a(typeof(Stringifyable))) { return i => ((Stringifyable)i).to_string(); }
        else if(type.is_a(typeof(BinaryData))) { return i => "0x" + ((BinaryData)i).to_hex(); }
        return i => @"[$(type.name()) at 0x$(((int)i).to_string("%x"))]";
    }

}