/// <summary>
/// Initializes a new instance of the <see cref="Option"/> class.
/// </summary>
/// <param name="aliases">The set of strings that can be used on the command line to specify the option.</param>
/// <param name="description">The description of the option shown in help.</param>
/// <param name="argumentType">The type that the option's argument(s) can be parsed to.</param>
/// <param name="getDefaultValue">A delegate used to get a default value for the option when it is not specified on the command line.</param>
/// <param name="arity">The arity of the option.</param>
public Option(
string[] aliases,
string?description = null,
Type?argumentType = null,
Func <object?>?getDefaultValue = null,
ArgumentArity arity = default)
: this(aliases, description, CreateArgument(argumentType, getDefaultValue, arity))
{
}
public static ConvertArgument DefaultConvertArgument(Type type) =>
symbol =>
{
switch (ArgumentArity.DefaultForType(type).MaximumNumberOfArguments)
{
case 1:
return(Parse(type, symbol.Arguments.SingleOrDefault()));
default:
return(ParseMany(type, symbol.Arguments));
}
};
private static Argument?CreateArgument(Type?argumentType, Func <object?>?getDefaultValue, ArgumentArity arity)
{
if (argumentType is null &&
getDefaultValue is null &&
!arity.IsNonDefault)
{
return(null);
}
var rv = new Argument();
if (argumentType is not null)
{
rv.ValueType = argumentType;
}
if (getDefaultValue is not null)
{
rv.SetDefaultValueFactory(getDefaultValue);
}
if (arity.IsNonDefault)
{
rv.Arity = arity;
}
return(rv);
}