Depending on constructor, we construct the object as follows:
"numeric_version": We usenumeric_version()"next": Use the constructor for the next supported class. Call.class2()on the object to see in which order the methods will be tried. This will usually be equivalent to"list""list": We define as a list and repair attributes
Usage
opts_numeric_version(constructor = c("numeric_version", "next", "list"), ...)