// // Options.cs // // Authors: // Jonathan Pryor // // 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), 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 { public class OptionValueCollection : IList, IList { List values = new List (); 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 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 public IEnumerator 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 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 ToList () { return new List (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 (); } #if NOTYPECONVERTER protected static T Parse (string value, OptionContext c) { if (typeof (T) == typeof (int)) return (T) (object) int.Parse (value); else if (typeof (T) == typeof (string)) return (T) (object) value; throw new OptionException ("Could not convert parameter", c.OptionName, null); } #else protected static T Parse (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; } #endif 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 seps = new List (); 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 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 key, TValue value); public class OptionSet : KeyedCollection { public OptionSet () : this (delegate (string f) {return f;}) { } public OptionSet (Converter localizer) { this.localizer = localizer; } Converter localizer; public Converter 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 added = new List (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 action; public ActionOption (string prototype, string description, int count, Action 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 action) { return Add (prototype, null, action); } public OptionSet Add (string prototype, string description, Action 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 action) { return Add (prototype, null, action); } public OptionSet Add (string prototype, string description, OptionAction 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 : Option { Action action; public ActionOption (string prototype, string description, Action action) : base (prototype, description, 1) { if (action == null) throw new ArgumentNullException ("action"); this.action = action; } protected override void OnParseComplete (OptionContext c) { action (Parse (c.OptionValues [0], c)); } } sealed class ActionOption : Option { OptionAction action; public ActionOption (string prototype, string description, OptionAction action) : base (prototype, description, 2) { if (action == null) throw new ArgumentNullException ("action"); this.action = action; } protected override void OnParseComplete (OptionContext c) { action ( Parse (c.OptionValues [0], c), Parse (c.OptionValues [1], c)); } } public OptionSet Add (string prototype, Action action) { return Add (prototype, null, action); } public OptionSet Add (string prototype, string description, Action action) { return Add (new ActionOption (prototype, description, action)); } public OptionSet Add (string prototype, OptionAction action) { return Add (prototype, null, action); } public OptionSet Add (string prototype, string description, OptionAction action) { return Add (new ActionOption (prototype, description, action)); } protected virtual OptionContext CreateOptionContext () { return new OptionContext (this); } #if LINQ public List Parse (IEnumerable 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 r = unprocessed.ToList (); if (c.Option != null) c.Option.Invoke (c); return r; } #else public List Parse (IEnumerable arguments) { OptionContext c = CreateOptionContext (); c.OptionIndex = -1; bool process = true; List unprocessed = new List (); 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 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 ( @"^(?--|-|/)(?[^:=]+)((?[:=])(?.*))?$"); 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 GetLines (string description) { if (string.IsNullOrEmpty (description)) { yield return string.Empty; yield break; } int length = 80 - OptionWidth - 1; int start = 0, end; do { end = GetLineEnd (start, length, description); char c = description [end-1]; if (char.IsWhiteSpace (c)) --end; bool writeContinuation = end != description.Length && !IsEolChar (c); string line = description.Substring (start, end - start) + (writeContinuation ? "-" : ""); yield return line; start = end; if (char.IsWhiteSpace (c)) ++start; length = 80 - OptionWidth - 2 - 1; } while (end < description.Length); } 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; } } }