As a design strategy, all function arguments have default values. Because of that, adding references gets a little clumsy. Generally, it's advised to avoid references in this way, however there are a couple workarounds:
Create a static dummy variable in the class and use it as the argument.
Use a pointer instead of a reference, and guard the presence of the pointer.
This topic could use a little more attention, for example quintessence could be modified to explicitly declare an argument without a default value. As is, the workarounds don't feel like the elegant final factoring of this feature.
As a design strategy, all function arguments have default values. Because of that, adding references gets a little clumsy. Generally, it's advised to avoid references in this way, however there are a couple workarounds:
This topic could use a little more attention, for example quintessence could be modified to explicitly declare an argument without a default value. As is, the workarounds don't feel like the elegant final factoring of this feature.