2010-06-03 Jb Evain <jbevain@novell.com>

[mcs.git] / class / Mono.Options / Mono.Options / Options.cs

//
// Options.cs
//
// Authors:
//  Jonathan Pryor <jpryor@novell.com>
//  Federico Di Gregorio <fog@initd.org>
//
// Copyright (C) 2008 Novell (http://www.novell.com)
// Copyright (C) 2009 Federico Di Gregorio.
//
// 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.Globalization;
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

#if NDESK_OPTIONS
namespace NDesk.Options
#else
namespace Mono.Options
#endif
{
        static class StringCoda {

                public static IEnumerable<string> WrappedLines (string self, params int[] widths)
                {
                        IEnumerable<int> w = widths;
                        return WrappedLines (self, w);
                }

                public static IEnumerable<string> WrappedLines (string self, IEnumerable<int> widths)
                {
                        if (widths == null)
                                throw new ArgumentNullException ("widths");
                        return CreateWrappedLinesIterator (self, widths);
                }

                private static IEnumerable<string> CreateWrappedLinesIterator (string self, IEnumerable<int> widths)
                {
                        if (string.IsNullOrEmpty (self)) {
                                yield return string.Empty;
                                yield break;
                        }
                        using (var ewidths = widths.GetEnumerator ()) {
                                bool? hw = null;
                                int width = GetNextWidth (ewidths, int.MaxValue, ref hw);
                                int start = 0, end;
                                do {
                                        end = GetLineEnd (start, width, self);
                                        char c = self [end-1];
                                        if (char.IsWhiteSpace (c))
                                                --end;
                                        bool needContinuation = end != self.Length && !IsEolChar (c);
                                        string continuation = "";
                                        if (needContinuation) {
                                                --end;
                                                continuation = "-";
                                        }
                                        string line = self.Substring (start, end - start) + continuation;
                                        yield return line;
                                        start = end;
                                        if (char.IsWhiteSpace (c))
                                                ++start;
                                        width = GetNextWidth (ewidths, width, ref hw);
                                } while (end < self.Length);
                        }
                }

                private static int GetNextWidth (IEnumerator<int> ewidths, int curWidth, ref bool? eValid)
                {
                        if (!eValid.HasValue || (eValid.HasValue && eValid.Value)) {
                                curWidth = (eValid = ewidths.MoveNext ()).Value ? ewidths.Current : curWidth;
                                // '.' is any character, - is for a continuation
                                const string minWidth = ".-";
                                if (curWidth < minWidth.Length)
                                        throw new ArgumentOutOfRangeException ("widths",
                                                        string.Format ("Element must be >= {0}, was {1}.", minWidth.Length, curWidth));
                                return curWidth;
                        }
                        // no more elements, use the last element.
                        return curWidth;
                }

                private static bool IsEolChar (char c)
                {
                        return !char.IsLetterOrDigit (c);
                }

                private static int GetLineEnd (int start, int length, string description)
                {
                        int end = System.Math.Min (start + length, description.Length);
                        int sep = -1;
                        for (int i = start; i < end; ++i) {
                                if (description [i] == '\n')
                                        return i+1;
                                if (IsEolChar (description [i]))
                                        sep = i+1;
                        }
                        if (sep == -1 || end == description.Length)
                                return end;
                        return sep;
                }
        }

        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;
                        this.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;
                        this.names       = prototype.Split ('|');
                        this.description = description;
                        this.count       = maxValueCount;
                        this.type        = ParsePrototype ();

                        if (this.count == 0 && type != OptionValueType.None)
                                throw new ArgumentException (
                                                "Cannot provide maxValueCount of 0 for OptionValueType.Required or " +
                                                        "OptionValueType.Optional.",
                                                "maxValueCount");
                        if (this.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 && this.type != OptionValueType.None) ||
                                         (names.Length > 1 && this.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)
                {
                        Type tt = typeof (T);
                        bool nullable = tt.IsValueType && tt.IsGenericType && 
                                !tt.IsGenericTypeDefinition && 
                                tt.GetGenericTypeDefinition () == typeof (Nullable<>);
                        Type targetType = nullable ? tt.GetGenericArguments () [0] : typeof (T);
                        TypeConverter conv = TypeDescriptor.GetConverter (targetType);
                        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, targetType.Name, c.OptionName),
                                                c.OptionName, e);
                        }
                        return t;
                }

                internal string[] Names           {get {return names;}}
                internal string[] ValueSeparators {get {return separators;}}

                static readonly char[] NameTerminator = new char[]{'=', ':'};

                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)
                                        this.separators = new string[]{":", "="};
                                else if (seps.Count == 1 && seps [0].Length == 0)
                                        this.separators = null;
                                else
                                        this.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)
                {
                        this.option = optionName;
                }

                public OptionException (string message, string optionName, Exception innerException)
                        : base (message, innerException)
                {
                        this.option = optionName;
                }

                protected OptionException (SerializationInfo info, StreamingContext context)
                        : base (info, context)
                {
                        this.option = info.GetString ("OptionName");
                }

                public string OptionName {
                        get {return this.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 string[]{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].ToString ();
                                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));
                                }

                                bool indent = false;
                                string prefix = new string (' ', OptionWidth+2);
                                foreach (string line in GetLines (localizer (GetDescription (p.Description)))) {
                                        if (indent) 
                                                o.Write (prefix);
                                        o.WriteLine (line);
                                        indent = true;
                                }
                        }
                }

                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;
                        if (maxIndex == 1)
                                nameStart = new string[]{"{0:", "{"};
                        else
                                nameStart = new string[]{"{" + 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 IEnumerable<string> GetLines (string description)
                {
                        return StringCoda.WrappedLines (description, 
                                        80 - OptionWidth, 
                                        80 - OptionWidth - 2);
                }
        }
}