Valu("A1Carryvalue", OpARM64ADCzerocarry, c.config.Types.UInt64, 0, nil, "A1carry"), // 0+0+A1carry
			Valu("A2value", OpSelect0, c.config.Types.UInt64, 0, nil, "A2"),
			Valu("A2Carryvalue", OpARM64ADCzerocarry, c.config.Types.UInt64, 0, nil, "A2carry"), // 0+0+A2carry
			Valu("ValueSum", OpARM64ADD, c.config.Types.UInt64, 0, nil, "A1value", "A2value"),
			Valu("CarrySum", OpARM64ADD, c.config.Types.UInt64, 0, nil, "A1Carryvalue", "A2Carryvalue"),

                return ExecutionTimeValue.changingValue(new MappingProvider<OUT, IN>(type, value.getChangingValue(), transformer));
            }

            return ExecutionTimeValue.value(mapValue(context, value.toValue()));
        }
    }

    @Nonnull
    @Override
    protected Value<OUT> mapValue(EvaluationContext.ScopeContext context, Value<? extends IN> value) {

                return ExecutionTimeValue.changingValue(new FilteringProvider<>(value.toProvider(), spec));
            }

            return ExecutionTimeValue.value(filterValue(context, value.toValue()));
        }
    }

    @Override
    protected Value<? extends T> calculateOwnValue(ValueConsumer consumer) {
        try (EvaluationContext.ScopeContext context = openScope()) {
            beforeRead(context);

    val headers =
      Headers.Builder()
        .add("foo: bar")
        .add(" foo: baz") // Name leading whitespace is trimmed.
        .add("foo : bak") // Name trailing whitespace is trimmed.
        .add("\tkey\t:\tvalue\t") // '\t' also counts as whitespace
        .add("ping:  pong  ") // Value whitespace is trimmed.
        .add("kit:kat") // Space after colon is not required.
        .build()

                return ExecutionTimeValue.changingValue(new TransformBackedProvider<OUT, IN>(type, value.toProvider(), transformer));
            }

            return ExecutionTimeValue.value(mapValue(context, value.toValue()));
        }
    }

    @Override
    protected Value<? extends OUT> calculateOwnValue(ValueConsumer consumer) {
        try (EvaluationContext.ScopeContext context = openScope()) {
            beforeRead(context);

	keys := make([]string, len(settableFlags))
	i := 0
	for key := range settableFlags {
		keys[i] = key
		i++
	}
	sort.Strings(keys)
	w := new(tabwriter.Writer).Init(writer, 0, 8, 5, ' ', 0)
	fmt.Fprintf(w, "FLAG\tVALUE\tFROM\n")
	for _, flag := range keys {
		v := settableFlags[flag]
		fmt.Fprintf(w, "%s\t%s\t%v\n", flag, viper.GetString(flag), configSource(flag, v))
	}
	return w.Flush()
}

                visitor.execute(ExecutionTimeValue.missing());
            } else if (value.hasFixedValue()) {
                // transform preserving side effects
                visitor.execute(ExecutionTimeValue.value(value.toValue().transform(v -> ImmutableMap.of(key, v))));
            } else {
                visitor.execute(ExecutionTimeValue.changingValue(