/// <summary>
/// Writes formatted usage information.
/// </summary>
/// <param name="options">
/// The <see cref="OptionSet"/> to write usage information for.
/// </param>
/// <exception cref="NotSupportedException">
/// An option has an unsupported <see cref="OptionValueType"/>.
/// </exception>
private void WriteUsage(OptionSet options)
{
using (var indentedTextWriter = new IndentedTextWriter(OutWriter, " "))
{
indentedTextWriter.WriteLine();
indentedTextWriter.WriteLine($"Usage: {EntryAssemblyFileName} [options]");
indentedTextWriter.WriteLine();
indentedTextWriter.WriteLine("options:");
indentedTextWriter.Indent++;
var maxPrototypeLength = options.Max(option =>
{
switch (option.OptionValueType)
{
case OptionValueType.None:
return(option.Prototype.Length);
case OptionValueType.Optional:
return(option.Prototype.Length - 1 + "[=VALUE]".Length);
case OptionValueType.Required:
return(option.Prototype.Length + "VALUE".Length);
default:
throw new NotSupportedException($"Unknown {nameof(OptionValueType)}: '{option.OptionValueType}'.");
}
});
foreach (var option in options)
{
switch (option.OptionValueType)
{
case OptionValueType.None:
indentedTextWriter.WriteLine($"--{{0,-{maxPrototypeLength}}} {option.Description}", option.Prototype);
break;
case OptionValueType.Optional:
indentedTextWriter.WriteLine($"--{{0,-{maxPrototypeLength}}} {option.Description}", option.Prototype.TrimEnd(':') + "[=VALUE]");
break;
case OptionValueType.Required:
indentedTextWriter.WriteLine($"--{{0,-{maxPrototypeLength}}} {option.Description}", option.Prototype + "VALUE");
break;
}
}
indentedTextWriter.Indent--;
}
}
