public static bool TryParseAsEnum <TEnum>(
string value,
string optionName,
out TEnum result,
TEnum?defaultValue = null,
OptionValueProvider provider = null) where TEnum : struct
{
if (!TryParseAsEnum(value, out result, defaultValue, provider))
{
WriteParseError(value, optionName, provider?.GetHelpText() ?? OptionValue.GetDefaultHelpText <TEnum>());
return(false);
}
return(true);
}
private static void WriteParseError(string value, string optionName, OptionValueProvider provider)
{
string helpText = provider.GetHelpText();
WriteParseError(value, optionName, helpText);
}
public static bool TryParse(
IEnumerable <string> values,
string optionName,
OptionValueProvider provider,
out Filter filter,
bool allowNull = false,
NamePartKind defaultNamePart = NamePartKind.Name,
PatternOptions includedPatternOptions = PatternOptions.None)
{
filter = null;
string pattern = values.FirstOrDefault();
if (pattern == null)
{
if (allowNull)
{
return(true);
}
else
{
throw new InvalidOperationException($"Option '{OptionNames.GetHelpText(optionName)}' is required.");
}
}
TimeSpan matchTimeout = Regex.InfiniteMatchTimeout;
string groupName = null;
NamePartKind namePart = defaultNamePart;
string separator = null;
Func <Capture, bool> predicate = null;
List <string> options = null;
foreach (string option in values.Skip(1))
{
int index = option.IndexOf("=");
if (index != -1)
{
string key = option.Substring(0, index);
string value = option.Substring(index + 1);
if (OptionValues.Group.IsKeyOrShortKey(key))
{
groupName = value;
continue;
}
else if (OptionValues.ListSeparator.IsKeyOrShortKey(key))
{
separator = value;
continue;
}
else if (OptionValues.Part.IsKeyOrShortKey(key))
{
if (!TryParseAsEnum(value, out namePart, provider: OptionValueProviders.NamePartKindProvider))
{
string helpText = OptionValueProviders.NamePartKindProvider.GetHelpText();
WriteError($"Option '{OptionValues.Part.HelpValue}' has invalid value '{value}'. Allowed values: {helpText}.");
return(false);
}
continue;
}
else if (OptionValues.Timeout.IsKeyOrShortKey(key))
{
if (!TryParseMatchTimeout(value, out matchTimeout))
{
WriteError($"Option '{OptionValues.Timeout.HelpValue}' has invalid value '{value}'.");
return(false);
}
continue;
}
}
if (Expression.TryParse(option, out Expression expression))
{
if (OptionValues.Length.IsKeyOrShortKey(expression.Identifier))
{
try
{
predicate = PredicateHelpers.GetLengthPredicate(expression);
continue;
}
catch (ArgumentException)
{
WriteError($"Option '{OptionNames.GetHelpText(optionName)}' has invalid value '{option}'.");
return(false);
}
}
else
{
WriteError($"Option '{OptionNames.GetHelpText(optionName)}' has invalid value '{option}'. Allowed values: {provider.GetHelpText()}.");
return(false);
}
}
(options ?? (options = new List <string>())).Add(option);
}
if (!TryParseRegexOptions(options, optionName, out RegexOptions regexOptions, out PatternOptions patternOptions, includedPatternOptions, provider))
{
return(false);
}
switch (patternOptions & (PatternOptions.WholeWord | PatternOptions.WholeLine))
{
case PatternOptions.None:
case PatternOptions.WholeWord:
case PatternOptions.WholeLine:
{
break;
}
default:
{
WriteError($"Values '{OptionValueProviders.PatternOptionsProvider.GetValue(nameof(PatternOptions.WholeWord)).HelpValue}' and '{OptionValueProviders.PatternOptionsProvider.GetValue(nameof(PatternOptions.WholeLine)).HelpValue}' cannot be combined.");
return(false);
}
}
if ((patternOptions & PatternOptions.FromFile) != 0 &&
!FileSystemHelpers.TryReadAllText(pattern, out pattern))
{
return(false);
}
pattern = BuildPattern(pattern, patternOptions, separator);
Regex regex = null;
try
{
regex = new Regex(pattern, regexOptions, matchTimeout);
}
catch (ArgumentException ex)
{
WriteError(ex, $"Could not parse regular expression: {ex.Message}");
return(false);
}
int groupIndex = -1;
if (groupName != null)
{
groupIndex = regex.GroupNumberFromName(groupName);
if (groupIndex == -1)
{
string message = $"Group '{groupName}' does not exist.";
string[] groupNames = regex.GetGroupNames();
if (groupNames.Length > 1)
{
message += $" Existing group names: {TextHelpers.Join(", ", " and ", groupNames.Where(f => f != "0"))}.";
}
WriteError(message);
return(false);
}
}
filter = new Filter(
regex,
namePart: namePart,
groupNumber: groupIndex,
isNegative: (patternOptions & PatternOptions.Negative) != 0,
predicate);
return(true);
}