context: //
  // Options.cs
  //
  // Authors:
  //  Jonathan Pryor <jpryor@novell.com>
  //
  // Copyright (C) 2008 Novell (http://www.novell.com)
  //
  // Permission is hereby granted, free of charge, to any person obtaining
  // a copy of this software and associated documentation files (the
  // "Software"), to deal in the Software without restriction, including
  // without limitation the rights to use, copy, modify, merge, publish,
  // distribute, sublicense, and/or sell copies of the Software, and to
  // permit persons to whom the Software is furnished to do so, subject to
  // the following conditions:
  // 
  // The above copyright notice and this permission notice shall be
  // included in all copies or substantial portions of the Software.
  // 
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  //
  
  // Compile With:
  //   gmcs -debug+ -r:System.Core Options.cs -o:NDesk.Options.dll
  //   gmcs -debug+ -d:LINQ -r:System.Core Options.cs -o:NDesk.Options.dll
  //
  // The LINQ version just changes the implementation of
  // OptionSet.Parse(IEnumerable<string>), and confers no semantic changes.
  
  //
  // A Getopt::Long-inspired option parsing library for C#.
  //
  // NDesk.Options.OptionSet is built upon a key/value table, where the
  // key is a option format string and the value is a delegate that is 
  // invoked when the format string is matched.
  //
  // Option format strings:
  //  Regex-like BNF Grammar: 
  //    name: .+
  //    type: [=:]
  //    sep: ( [^{}]+ | '{' .+ '}' )?
  //    aliases: ( name type sep ) ( '|' name type sep )*
  // 
  // Each '|'-delimited name is an alias for the associated action.  If the
  // format string ends in a '=', it has a required value.  If the format
  // string ends in a ':', it has an optional value.  If neither '=' or ':'
  // is present, no value is supported.  `=' or `:' need only be defined on one
  // alias, but if they are provided on more than one they must be consistent.
  //
  // Each alias portion may also end with a "key/value separator", which is used
  // to split option values if the option accepts > 1 value.  If not specified,
  // it defaults to '=' and ':'.  If specified, it can be any character except
  // '{' and '}' OR the *string* between '{' and '}'.  If no separator should be
  // used (i.e. the separate values should be distinct arguments), then "{}"
  // should be used as the separator.
  //
  // Options are extracted either from the current option by looking for
  // the option name followed by an '=' or ':', or is taken from the
  // following option IFF:
  //  - The current option does not contain a '=' or a ':'
  //  - The current option requires a value (i.e. not a Option type of ':')
  //
  // The `name' used in the option format string does NOT include any leading
  // option indicator, such as '-', '--', or '/'.  All three of these are
  // permitted/required on any named option.
  //
  // Option bundling is permitted so long as:
  //   - '-' is used to start the option group
  //   - all of the bundled options are a single character
  //   - at most one of the bundled options accepts a value, and the value
  //     provided starts from the next character to the end of the string.
  //
  // This allows specifying '-a -b -c' as '-abc', and specifying '-D name=value'
  // as '-Dname=value'.
  //
  // Option processing is disabled by specifying "--".  All options after "--"
  // are returned by OptionSet.Parse() unchanged and unprocessed.
  //
  // Unprocessed options are returned from OptionSet.Parse().
  //
  // Examples:
  //  int verbose = 0;
  //  OptionSet p = new OptionSet ()
  //    .Add ("v", v => ++verbose)
  //    .Add ("name=|value=", v => Console.WriteLine (v));
  //  p.Parse (new string[]{"-v", "--v", "/v", "-name=A", "/name", "B", "extra"});
  //
  // The above would parse the argument string array, and would invoke the
  // lambda expression three times, setting `verbose' to 3 when complete.  
  // It would also print out "A" and "B" to standard output.
  // The returned array would contain the string "extra".
  //
  // C# 3.0 collection initializers are supported and encouraged:
  //  var p = new OptionSet () {
  //    { "h|?|help", v => ShowHelp () },
  //  };
  //
  // System.ComponentModel.TypeConverter is also supported, allowing the use of
  // custom data types in the callback type; TypeConverter.ConvertFromString()
  // is used to convert the value option to an instance of the specified
  // type:
  //
  //  var p = new OptionSet () {
  //    { "foo=", (Foo f) => Console.WriteLine (f.ToString ()) },
  //  };
  //
  // Random other tidbits:
  //  - Boolean options (those w/o '=' or ':' in the option format string)
  //    are explicitly enabled if they are followed with '+', and explicitly
  //    disabled if they are followed with '-':
  //      string a = null;
  //      var p = new OptionSet () {
  //        { "a", s => a = s },
  //      };
  //      p.Parse (new string[]{"-a"});   // sets v != null
  //      p.Parse (new string[]{"-a+"});  // sets v != null
  //      p.Parse (new string[]{"-a-"});  // sets v == null
  //
  
  using System;
  using System.Collections;
  using System.Collections.Generic;
  using System.Collections.ObjectModel;
  using System.ComponentModel;
  using System.IO;
  using System.Runtime.Serialization;
  using System.Security.Permissions;
  using System.Text;
  using System.Text.RegularExpressions;
  
  #if LINQ
  using System.Linq;
  #endif
  
  #if TEST
  using NDesk.Options;
  #endif
  
  namespace NDesk.Options
  {
      public class OptionValueCollection : IList, IList<string>
      {
          List<string> values = new List<string>();
          OptionContext c;
  
          internal OptionValueCollection(OptionContext c)
          {
              this.c = c;
          }
  
          #region ICollection
  
          void ICollection.CopyTo(Array array, int index)
          {
              (values as ICollection).CopyTo(array, index);
          }
  
          bool ICollection.IsSynchronized
          {
              get { return (values as ICollection).IsSynchronized; }
          }
  
          object ICollection.SyncRoot
          {
              get { return (values as ICollection).SyncRoot; }
          }
  
          #endregion
  
          #region ICollection<T>
  
          public void Add(string item)
          {
              values.Add(item);
          }
  
          public void Clear()
          {
              values.Clear();
          }
  
          public bool Contains(string item)
          {
              return values.Contains(item);
          }
  
          public void CopyTo(string[] array, int arrayIndex)
          {
              values.CopyTo(array, arrayIndex);
          }
  
          public bool Remove(string item)
          {
              return values.Remove(item);
          }
  
          public int Count
          {
              get { return values.Count; }
          }
  
          public bool IsReadOnly
          {
              get { return false; }
          }
  
          #endregion
  
          #region IEnumerable
  
          IEnumerator IEnumerable.GetEnumerator()
          {
              return values.GetEnumerator();
          }
  
          #endregion
  
          #region IEnumerable<T>
  
          public IEnumerator<string> GetEnumerator()
          {
              return values.GetEnumerator();
          }
  
          #endregion
  
          #region IList
  
          int IList.Add(object value)
          {
              return (values as IList).Add(value);
          }
  
          bool IList.Contains(object value)
          {
              return (values as IList).Contains(value);
          }
  
          int IList.IndexOf(object value)
          {
              return (values as IList).IndexOf(value);
          }
  
          void IList.Insert(int index, object value)
          {
              (values as IList).Insert(index, value);
          }
  
          void IList.Remove(object value)
          {
              (values as IList).Remove(value);
          }
  
          void IList.RemoveAt(int index)
          {
              (values as IList).RemoveAt(index);
          }
  
          bool IList.IsFixedSize
          {
              get { return false; }
          }
  
          object IList.this[int index]
          {
              get { return this[index]; }
              set { (values as IList)[index] = value; }
          }
  
          #endregion
  
          #region IList<T>
  
          public int IndexOf(string item)
          {
              return values.IndexOf(item);
          }
  
          public void Insert(int index, string item)
          {
              values.Insert(index, item);
          }
  
          public void RemoveAt(int index)
          {
              values.RemoveAt(index);
          }
  
          private void AssertValid(int index)
          {
              if (c.Option == null)
                  throw new InvalidOperationException("OptionContext.Option is null.");
              if (index >= c.Option.MaxValueCount)
                  throw new ArgumentOutOfRangeException("index");
              if (c.Option.OptionValueType == OptionValueType.Required &&
                  index >= values.Count)
                  throw new OptionException(string.Format(
                          c.OptionSet.MessageLocalizer("Missing required value for option '{0}'."), c.OptionName),
                      c.OptionName);
          }
  
          public string this[int index]
          {
              get
              {
                  AssertValid(index);
                  return index >= values.Count ? null : values[index];
              }
              set { values[index] = value; }
          }
  
          #endregion
  
          public List<string> ToList()
          {
              return new List<string>(values);
          }
  
          public string[] ToArray()
          {
              return values.ToArray();
          }
  
          public override string ToString()
          {
              return string.Join(", ", values.ToArray());
          }
      }
  
      public class OptionContext
      {
          private Option option;
          private string name;
          private int index;
          private OptionSet set;
          private OptionValueCollection c;
  
          public OptionContext(OptionSet set)
          {
              this.set = set;
              c = new OptionValueCollection(this);
          }
  
          public Option Option
          {
              get { return option; }
              set { option = value; }
          }
  
          public string OptionName
          {
              get { return name; }
              set { name = value; }
          }
  
          public int OptionIndex
          {
              get { return index; }
              set { index = value; }
          }
  
          public OptionSet OptionSet
          {
              get { return set; }
          }
  
          public OptionValueCollection OptionValues
          {
              get { return c; }
          }
      }
  
      public enum OptionValueType
      {
          None,
          Optional,
          Required
      }
  
      public abstract class Option
      {
          string prototype, description;
          string[] names;
          OptionValueType type;
          int count;
          string[] separators;
  
          protected Option(string prototype, string description)
              : this(prototype, description, 1) { }
  
          protected Option(string prototype, string description, int maxValueCount)
          {
              if (prototype == null)
                  throw new ArgumentNullException("prototype");
              if (prototype.Length == 0)
                  throw new ArgumentException("Cannot be the empty string.", "prototype");
              if (maxValueCount < 0)
                  throw new ArgumentOutOfRangeException("maxValueCount");
  
              this.prototype = prototype;
              names = prototype.Split('|');
              this.description = description;
              count = maxValueCount;
              type = ParsePrototype();
  
              if (count == 0 && type != OptionValueType.None)
                  throw new ArgumentException(
                      "Cannot provide maxValueCount of 0 for OptionValueType.Required or " +
                      "OptionValueType.Optional.",
                      "maxValueCount");
              if (type == OptionValueType.None && maxValueCount > 1)
                  throw new ArgumentException(
                      string.Format("Cannot provide maxValueCount of {0} for OptionValueType.None.", maxValueCount),
                      "maxValueCount");
              if (Array.IndexOf(names, "<>") >= 0 &&
                  ((names.Length == 1 && type != OptionValueType.None) ||
                   (names.Length > 1 && MaxValueCount > 1)))
                  throw new ArgumentException(
                      "The default option handler '<>' cannot require values.",
                      "prototype");
          }
  
          public string Prototype
          {
              get { return prototype; }
          }
  
          public string Description
          {
              get { return description; }
          }
  
          public OptionValueType OptionValueType
          {
              get { return type; }
          }
  
          public int MaxValueCount
          {
              get { return count; }
          }
  
          public string[] GetNames()
          {
              return (string[]) names.Clone();
          }
  
          public string[] GetValueSeparators()
          {
              if (separators == null)
                  return new string [0];
              return (string[]) separators.Clone();
          }
  
          protected static T Parse<T>(string value, OptionContext c)
          {
              TypeConverter conv = TypeDescriptor.GetConverter(typeof(T));
              T t = default(T);
              try
              {
                  if (value != null)
                      t = (T) conv.ConvertFromString(value);
              }
              catch (Exception e)
              {
                  throw new OptionException(
                      string.Format(
                          c.OptionSet.MessageLocalizer("Could not convert string `{0}' to type {1} for option `{2}'."),
                          value, typeof(T).Name, c.OptionName),
                      c.OptionName, e);
              }
              return t;
          }
  
          internal string[] Names
          {
              get { return names; }
          }
  
          internal string[] ValueSeparators
          {
              get { return separators; }
          }
  
          static readonly char[] NameTerminator = {'=', ':'};
  
          private OptionValueType ParsePrototype()
          {
              char type = '\0';
              List<string> seps = new List<string>();
              for (int i = 0; i < names.Length; ++i)
              {
                  string name = names[i];
                  if (name.Length == 0)
                      throw new ArgumentException("Empty option names are not supported.", "prototype");
  
                  int end = name.IndexOfAny(NameTerminator);
                  if (end == -1)
                      continue;
                  names[i] = name.Substring(0, end);
                  if (type == '\0' || type == name[end])
                      type = name[end];
                  else
                      throw new ArgumentException(
                          string.Format("Conflicting option types: '{0}' vs. '{1}'.", type, name[end]),
                          "prototype");
                  AddSeparators(name, end, seps);
              }
  
              if (type == '\0')
                  return OptionValueType.None;
  
              if (count <= 1 && seps.Count != 0)
                  throw new ArgumentException(
                      string.Format("Cannot provide key/value separators for Options taking {0} value(s).", count),
                      "prototype");
              if (count > 1)
              {
                  if (seps.Count == 0)
                      separators = new[] {":", "="};
                  else if (seps.Count == 1 && seps[0].Length == 0)
                      separators = null;
                  else
                      separators = seps.ToArray();
              }
  
              return type == '=' ? OptionValueType.Required : OptionValueType.Optional;
          }
  
          private static void AddSeparators(string name, int end, ICollection<string> seps)
          {
              int start = -1;
              for (int i = end + 1; i < name.Length; ++i)
              {
                  switch (name[i])
                  {
                      case '{':
                          if (start != -1)
                              throw new ArgumentException(
                                  string.Format("Ill-formed name/value separator found in \"{0}\".", name),
                                  "prototype");
                          start = i + 1;
                          break;
                      case '}':
                          if (start == -1)
                              throw new ArgumentException(
                                  string.Format("Ill-formed name/value separator found in \"{0}\".", name),
                                  "prototype");
                          seps.Add(name.Substring(start, i - start));
                          start = -1;
                          break;
                      default:
                          if (start == -1)
                              seps.Add(name[i].ToString());
                          break;
                  }
              }
              if (start != -1)
                  throw new ArgumentException(
                      string.Format("Ill-formed name/value separator found in \"{0}\".", name),
                      "prototype");
          }
  
          public void Invoke(OptionContext c)
          {
              OnParseComplete(c);
              c.OptionName = null;
              c.Option = null;
              c.OptionValues.Clear();
          }
  
          protected abstract void OnParseComplete(OptionContext c);
  
          public override string ToString()
          {
              return Prototype;
          }
      }
  
      [Serializable]
      public class OptionException : Exception
      {
          private string option;
  
          public OptionException() { }
  
          public OptionException(string message, string optionName)
              : base(message)
          {
              option = optionName;
          }
  
          public OptionException(string message, string optionName, Exception innerException)
              : base(message, innerException)
          {
              option = optionName;
          }
  
          protected OptionException(SerializationInfo info, StreamingContext context)
              : base(info, context)
          {
              option = info.GetString("OptionName");
          }
  
          public string OptionName
          {
              get { return option; }
          }
  
          [SecurityPermission(SecurityAction.LinkDemand, SerializationFormatter = true)]
          public override void GetObjectData(SerializationInfo info, StreamingContext context)
          {
              base.GetObjectData(info, context);
              info.AddValue("OptionName", option);
          }
      }
  
      public delegate void OptionAction<TKey, TValue>(TKey key, TValue value);
  
      public class OptionSet : KeyedCollection<string, Option>
      {
          public OptionSet()
              : this(delegate(string f) { return f; }) { }
  
          public OptionSet(Converter<string, string> localizer)
          {
              this.localizer = localizer;
          }
  
          Converter<string, string> localizer;
  
          public Converter<string, string> MessageLocalizer
          {
              get { return localizer; }
          }
  
          protected override string GetKeyForItem(Option item)
          {
              if (item == null)
                  throw new ArgumentNullException("option");
              if (item.Names != null && item.Names.Length > 0)
                  return item.Names[0];
              // This should never happen, as it's invalid for Option to be
              // constructed w/o any names.
              throw new InvalidOperationException("Option has no names!");
          }
  
          [Obsolete("Use KeyedCollection.this[string]")]
          protected Option GetOptionForName(string option)
          {
              if (option == null)
                  throw new ArgumentNullException("option");
              try
              {
                  return base[option];
              }
              catch (KeyNotFoundException)
              {
                  return null;
              }
          }
  
          protected override void InsertItem(int index, Option item)
          {
              base.InsertItem(index, item);
              AddImpl(item);
          }
  
          protected override void RemoveItem(int index)
          {
              base.RemoveItem(index);
              Option p = Items[index];
              // KeyedCollection.RemoveItem() handles the 0th item
              for (int i = 1; i < p.Names.Length; ++i)
              {
                  Dictionary.Remove(p.Names[i]);
              }
          }
  
          protected override void SetItem(int index, Option item)
          {
              base.SetItem(index, item);
              RemoveItem(index);
              AddImpl(item);
          }
  
          private void AddImpl(Option option)
          {
              if (option == null)
                  throw new ArgumentNullException("option");
              List<string> added = new List<string>(option.Names.Length);
              try
              {
                  // KeyedCollection.InsertItem/SetItem handle the 0th name.
                  for (int i = 1; i < option.Names.Length; ++i)
                  {
                      Dictionary.Add(option.Names[i], option);
                      added.Add(option.Names[i]);
                  }
              }
              catch (Exception)
              {
                  foreach (string name in added)
                      Dictionary.Remove(name);
                  throw;
              }
          }
  
          public new OptionSet Add(Option option)
          {
              base.Add(option);
              return this;
          }
  
          sealed class ActionOption : Option
          {
              Action<OptionValueCollection> action;
  
              public ActionOption(string prototype, string description, int count, Action<OptionValueCollection> action)
                  : base(prototype, description, count)
              {
                  if (action == null)
                      throw new ArgumentNullException("action");
                  this.action = action;
              }
  
              protected override void OnParseComplete(OptionContext c)
              {
                  action(c.OptionValues);
              }
          }
  
          public OptionSet Add(string prototype, Action<string> action)
          {
              return Add(prototype, null, action);
          }
  
          public OptionSet Add(string prototype, string description, Action<string> action)
          {
              if (action == null)
                  throw new ArgumentNullException("action");
              Option p = new ActionOption(prototype, description, 1,
                  delegate(OptionValueCollection v) { action(v[0]); });
              base.Add(p);
              return this;
          }
  
          public OptionSet Add(string prototype, OptionAction<string, string> action)
          {
              return Add(prototype, null, action);
          }
  
          public OptionSet Add(string prototype, string description, OptionAction<string, string> action)
          {
              if (action == null)
                  throw new ArgumentNullException("action");
              Option p = new ActionOption(prototype, description, 2,
                  delegate(OptionValueCollection v) { action(v[0], v[1]); });
              base.Add(p);
              return this;
          }
  
          sealed class ActionOption<T> : Option
          {
              Action<T> action;
  
              public ActionOption(string prototype, string description, Action<T> action)
                  : base(prototype, description, 1)
              {
                  if (action == null)
                      throw new ArgumentNullException("action");
                  this.action = action;
              }
  
              protected override void OnParseComplete(OptionContext c)
              {
                  action(Parse<T>(c.OptionValues[0], c));
              }
          }
  
          sealed class ActionOption<TKey, TValue> : Option
          {
              OptionAction<TKey, TValue> action;
  
              public ActionOption(string prototype, string description, OptionAction<TKey, TValue> action)
                  : base(prototype, description, 2)
              {
                  if (action == null)
                      throw new ArgumentNullException("action");
                  this.action = action;
              }
  
              protected override void OnParseComplete(OptionContext c)
              {
                  action(
                      Parse<TKey>(c.OptionValues[0], c),
                      Parse<TValue>(c.OptionValues[1], c));
              }
          }
  
          public OptionSet Add<T>(string prototype, Action<T> action)
          {
              return Add(prototype, null, action);
          }
  
          public OptionSet Add<T>(string prototype, string description, Action<T> action)
          {
              return Add(new ActionOption<T>(prototype, description, action));
          }
  
          public OptionSet Add<TKey, TValue>(string prototype, OptionAction<TKey, TValue> action)
          {
              return Add(prototype, null, action);
          }
  
          public OptionSet Add<TKey, TValue>(string prototype, string description, OptionAction<TKey, TValue> action)
          {
              return Add(new ActionOption<TKey, TValue>(prototype, description, action));
          }
  
          protected virtual OptionContext CreateOptionContext()
          {
              return new OptionContext(this);
          }
  
  #if LINQ
  		public List<string> Parse (IEnumerable<string> arguments)
  		{
  			bool process = true;
  			OptionContext c = CreateOptionContext ();
  			c.OptionIndex = -1;
  			var def = GetOptionForName ("<>");
  			var unprocessed =
  				from argument in arguments
  				where ++c.OptionIndex >= 0 && (process || def != null)
  					? process
  						? argument == "--" 
  							? (process = false)
  							: !Parse (argument, c)
  								? def != null 
  									? Unprocessed (null, def, c, argument) 
  									: true
  								: false
  						: def != null 
  							? Unprocessed (null, def, c, argument)
  							: true
  					: true
  				select argument;
  			List<string> r = unprocessed.ToList ();
  			if (c.Option != null)
  				c.Option.Invoke (c);
  			return r;
  		}
  #else
          public List<string> Parse(IEnumerable<string> arguments)
          {
              OptionContext c = CreateOptionContext();
              c.OptionIndex = -1;
              bool process = true;
              List<string> unprocessed = new List<string>();
              Option def = Contains("<>") ? this["<>"] : null;
              foreach (string argument in arguments)
              {
                  ++c.OptionIndex;
                  if (argument == "--")
                  {
                      process = false;
                      continue;
                  }
                  if (!process)
                  {
                      Unprocessed(unprocessed, def, c, argument);
                      continue;
                  }
                  if (!Parse(argument, c))
                      Unprocessed(unprocessed, def, c, argument);
              }
              if (c.Option != null)
                  c.Option.Invoke(c);
              return unprocessed;
          }
  #endif
  
          private static bool Unprocessed(ICollection<string> extra, Option def, OptionContext c, string argument)
          {
              if (def == null)
              {
                  extra.Add(argument);
                  return false;
              }
              c.OptionValues.Add(argument);
              c.Option = def;
              c.Option.Invoke(c);
              return false;
          }
  
          private readonly Regex ValueOption = new Regex(
              @"^(?<flag>--|-|/)(?<name>[^:=]+)((?<sep>[:=])(?<value>.*))?$");
  
          protected bool GetOptionParts(string argument, out string flag, out string name, out string sep,
              out string value)
          {
              if (argument == null)
                  throw new ArgumentNullException("argument");
  
              flag = name = sep = value = null;
              Match m = ValueOption.Match(argument);
              if (!m.Success)
              {
                  return false;
              }
              flag = m.Groups["flag"].Value;
              name = m.Groups["name"].Value;
              if (m.Groups["sep"].Success && m.Groups["value"].Success)
              {
                  sep = m.Groups["sep"].Value;
                  value = m.Groups["value"].Value;
              }
              return true;
          }
  
          protected virtual bool Parse(string argument, OptionContext c)
          {
              if (c.Option != null)
              {
                  ParseValue(argument, c);
                  return true;
              }
  
              string f, n, s, v;
              if (!GetOptionParts(argument, out f, out n, out s, out v))
                  return false;
  
              Option p;
              if (Contains(n))
              {
                  p = this[n];
                  c.OptionName = f + n;
                  c.Option = p;
                  switch (p.OptionValueType)
                  {
                      case OptionValueType.None:
                          c.OptionValues.Add(n);
                          c.Option.Invoke(c);
                          break;
                      case OptionValueType.Optional:
                      case OptionValueType.Required:
                          ParseValue(v, c);
                          break;
                  }
                  return true;
              }
              // no match; is it a bool option?
              if (ParseBool(argument, n, c))
                  return true;
              // is it a bundled option?
              if (ParseBundledValue(f, string.Concat(n + s + v), c))
                  return true;
  
              return false;
          }
  
          private void ParseValue(string option, OptionContext c)
          {
              if (option != null)
                  foreach (string o in c.Option.ValueSeparators != null
                      ? option.Split(c.Option.ValueSeparators, StringSplitOptions.None)
                      : new[] {option})
                  {
                      c.OptionValues.Add(o);
                  }
              if (c.OptionValues.Count == c.Option.MaxValueCount ||
                  c.Option.OptionValueType == OptionValueType.Optional)
                  c.Option.Invoke(c);
              else if (c.OptionValues.Count > c.Option.MaxValueCount)
              {
                  throw new OptionException(localizer(string.Format(
                          "Error: Found {0} option values when expecting {1}.",
                          c.OptionValues.Count, c.Option.MaxValueCount)),
                      c.OptionName);
              }
          }
  
          private bool ParseBool(string option, string n, OptionContext c)
          {
              Option p;
              string rn;
              if (n.Length >= 1 && (n[n.Length - 1] == '+' || n[n.Length - 1] == '-') &&
                  Contains((rn = n.Substring(0, n.Length - 1))))
              {
                  p = this[rn];
                  string v = n[n.Length - 1] == '+' ? option : null;
                  c.OptionName = option;
                  c.Option = p;
                  c.OptionValues.Add(v);
                  p.Invoke(c);
                  return true;
              }
              return false;
          }
  
          private bool ParseBundledValue(string f, string n, OptionContext c)
          {
              if (f != "-")
                  return false;
              for (int i = 0; i < n.Length; ++i)
              {
                  Option p;
                  string opt = f + n[i];
                  string rn = n[i].ToString();
                  if (!Contains(rn))
                  {
                      if (i == 0)
                          return false;
                      throw new OptionException(string.Format(localizer(
                          "Cannot bundle unregistered option '{0}'."), opt), opt);
                  }
                  p = this[rn];
                  switch (p.OptionValueType)
                  {
                      case OptionValueType.None:
                          Invoke(c, opt, n, p);
                          break;
                      case OptionValueType.Optional:
                      case OptionValueType.Required:
                      {
                          string v = n.Substring(i + 1);
                          c.Option = p;
                          c.OptionName = opt;
                          ParseValue(v.Length != 0 ? v : null, c);
                          return true;
                      }
                      default:
                          throw new InvalidOperationException("Unknown OptionValueType: " + p.OptionValueType);
                  }
              }
              return true;
          }
  
          private static void Invoke(OptionContext c, string name, string value, Option option)
          {
              c.OptionName = name;
              c.Option = option;
              c.OptionValues.Add(value);
              option.Invoke(c);
          }
  
          private const int OptionWidth = 29;
  
          public void WriteOptionDescriptions(TextWriter o)
          {
              foreach (Option p in this)
              {
                  int written = 0;
                  if (!WriteOptionPrototype(o, p, ref written))
                      continue;
  
                  if (written < OptionWidth)
                      o.Write(new string(' ', OptionWidth - written));
                  else
                  {
                      o.WriteLine();
                      o.Write(new string(' ', OptionWidth));
                  }
  
                  List<string> lines = GetLines(localizer(GetDescription(p.Description)));
                  o.WriteLine(lines[0]);
                  string prefix = new string(' ', OptionWidth + 2);
                  for (int i = 1; i < lines.Count; ++i)
                  {
                      o.Write(prefix);
                      o.WriteLine(lines[i]);
                  }
              }
          }
  
          bool WriteOptionPrototype(TextWriter o, Option p, ref int written)
          {
              string[] names = p.Names;
  
              int i = GetNextOptionIndex(names, 0);
              if (i == names.Length)
                  return false;
  
              if (names[i].Length == 1)
              {
                  Write(o, ref written, "  -");
                  Write(o, ref written, names[0]);
              }
              else
              {
                  Write(o, ref written, "      --");
                  Write(o, ref written, names[0]);
              }
  
              for (i = GetNextOptionIndex(names, i + 1);
                  i < names.Length;
                  i = GetNextOptionIndex(names, i + 1))
              {
                  Write(o, ref written, ", ");
                  Write(o, ref written, names[i].Length == 1 ? "-" : "--");
                  Write(o, ref written, names[i]);
              }
  
              if (p.OptionValueType == OptionValueType.Optional ||
                  p.OptionValueType == OptionValueType.Required)
              {
                  if (p.OptionValueType == OptionValueType.Optional)
                  {
                      Write(o, ref written, localizer("["));
                  }
                  Write(o, ref written, localizer("=" + GetArgumentName(0, p.MaxValueCount, p.Description)));
                  string sep = p.ValueSeparators != null && p.ValueSeparators.Length > 0
                      ? p.ValueSeparators[0]
                      : " ";
                  for (int c = 1; c < p.MaxValueCount; ++c)
                  {
                      Write(o, ref written, localizer(sep + GetArgumentName(c, p.MaxValueCount, p.Description)));
                  }
                  if (p.OptionValueType == OptionValueType.Optional)
                  {
                      Write(o, ref written, localizer("]"));
                  }
              }
              return true;
          }
  
          static int GetNextOptionIndex(string[] names, int i)
          {
              while (i < names.Length && names[i] == "<>")
              {
                  ++i;
              }
              return i;
          }
  
          static void Write(TextWriter o, ref int n, string s)
          {
              n += s.Length;
              o.Write(s);
          }
  
          private static string GetArgumentName(int index, int maxIndex, string description)
          {
              if (description == null)
                  return maxIndex == 1 ? "VALUE" : "VALUE" + (index + 1);
              string[] nameStart;
              nameStart = maxIndex == 1 ? new[] {"{0:", "{"} : new[] {"{" + index + ":"};
              for (int i = 0; i < nameStart.Length; ++i)
              {
                  int start, j = 0;
                  do
                  {
                      start = description.IndexOf(nameStart[i], j);
                  } while (start >= 0 && j != 0 ? description[j++ - 1] == '{' : false);
                  if (start == -1)
                      continue;
                  int end = description.IndexOf("}", start);
                  if (end == -1)
                      continue;
                  return description.Substring(start + nameStart[i].Length, end - start - nameStart[i].Length);
              }
              return maxIndex == 1 ? "VALUE" : "VALUE" + (index + 1);
          }
  
          private static string GetDescription(string description)
          {
              if (description == null)
                  return string.Empty;
              StringBuilder sb = new StringBuilder(description.Length);
              int start = -1;
              for (int i = 0; i < description.Length; ++i)
              {
                  switch (description[i])
                  {
                      case '{':
                          if (i == start)
                          {
                              sb.Append('{');
                              start = -1;
                          }
                          else if (start < 0)
                              start = i + 1;
                          break;
                      case '}':
                          if (start < 0)
                          {
                              if ((i + 1) == description.Length || description[i + 1] != '}')
                                  throw new InvalidOperationException("Invalid option description: " + description);
                              ++i;
                              sb.Append("}");
                          }
                          else
                          {
                              sb.Append(description.Substring(start, i - start));
                              start = -1;
                          }
                          break;
                      case ':':
                          if (start < 0)
                              goto default;
                          start = i + 1;
                          break;
                      default:
                          if (start < 0)
                              sb.Append(description[i]);
                          break;
                  }
              }
              return sb.ToString();
          }
  
          private static List<string> GetLines(string description)
          {
  
gt:             List<string> lines = new List<string>();