Common Valued Option Properties

All non-flag options in Clon are said to be valued. All valued options, including those you define yourself (see New Option Types), share a set of additional properties. Here is a list of them.


The name of the option’s argument, as it appears in the help string. It defaults to "ARG", so that for instance, a ‘name’ option would appear like this: ‘--name=ARG’.


The status of the argument. Possible values are :required (the default) and :mandatory which are synonyms, or :optional.


The option’s fallback and default values. Remember that a fallback value only makes sense when the argument is optional. Besides, also when the argument is optional, you need to provide at least a fallback or a default value (or both of course; see Value Sources in The Clon End-User Manual).