The line that would be printed as definition of this arg in help output.
Converter for pure string arguments to the needed type of this option.
Function that provides an optional default value for this option.
Description for this option that will be presented to the user
List of argument lines, descriptions to them, and optional default values.
If true, then this option is not shown in help output.
True for trailing argument option type, false for everything else.
Long names for this option.
Internal name of this option - the one that would be used to access parsed values.
Is there a requirement to have at least one invocation of this option?
Short names that were explicitly set for this option.
Short names that are suggested by option implementation.
Validator for the option value.
Parent class for option descriptors. Each option descriptor contains everything needed to parse that option - option names, defaults, converters, validators, etc.