/// <summary>
/// Creates a new instance of the <see cref="CommandLine.Text.HelpText"/> class using common defaults.
/// </summary>
/// <returns>
/// An instance of <see cref="CommandLine.Text.HelpText"/> class.
/// </returns>
/// <param name='parserResult'>The <see cref="CommandLine.ParserResult{T}"/> containing the instance that collected command line arguments parsed with <see cref="CommandLine.Parser"/> class.</param>
/// <param name='onError'>A delegate used to customize the text block of reporting parsing errors text block.</param>
/// <param name='onExample'>A delegate used to customize <see cref="CommandLine.Text.Example"/> model used to render text block of usage examples.</param>
/// <param name="verbsIndex">If true the output style is consistent with verb commands (no dashes), otherwise it outputs options.</param>
/// <remarks>The parameter <paramref name="verbsIndex"/> is not ontly a metter of formatting, it controls whether to handle verbs or options.</remarks>
public static HelpText AutoBuild <T>(
ParserResult <T> parserResult,
Func <HelpText, HelpText> onError,
Func <Example, Example> onExample,
bool verbsIndex = false)
{
var auto = new HelpText
{
Heading = HeadingInfo.Default,
Copyright = CopyrightInfo.Default,
AdditionalNewLineAfterOption = true,
AddDashesToOption = !verbsIndex
};
var errors = Enumerable.Empty <Error>();
if (onError != null && parserResult.Tag == ParserResultType.NotParsed)
{
errors = ((NotParsed <T>)parserResult).Errors;
if (errors.OnlyMeaningfulOnes().Any())
{
auto = onError(auto);
}
}
ReflectionHelper.GetAttribute <AssemblyLicenseAttribute>()
.Do(license => license.AddToHelpText(auto, true));
var usageAttr = ReflectionHelper.GetAttribute <AssemblyUsageAttribute>();
var usageLines = HelpText.RenderUsageTextAsLines(parserResult, onExample).ToMaybe();
if (usageAttr.IsJust() || usageLines.IsJust())
{
var heading = auto.SentenceBuilder.UsageHeadingText();
if (heading.Length > 0)
{
auto.AddPreOptionsLine(heading);
}
}
usageAttr.Do(
usage => usage.AddToHelpText(auto, true));
usageLines.Do(
lines => auto.AddPreOptionsLines(lines));
if ((verbsIndex && parserResult.TypeInfo.Choices.Any()) ||
errors.Any(e => e.Tag == ErrorType.NoVerbSelectedError))
{
auto.AddDashesToOption = false;
auto.AddVerbs(parserResult.TypeInfo.Choices.ToArray());
}
else
{
auto.AddOptions(parserResult);
}
return(auto);
}
