Org.Lwes/ESF/Exceptions.cs

   1 //
   2 // This file is part of the LWES .NET Binding (LWES.net)
   3 //
   4 // COPYRIGHT© 2009, Phillip Clark (phillip[at*flitbit[dot*org)
   5 //       original .NET implementation
   6 //
   7 // LWES.net is free software: you can redistribute it and/or modify
   8 // it under the terms of the Lesser GNU General Public License as published by
   9 // the Free Software Foundation, either version 3 of the License, or
  10 // (at your option) any later version.
  11 //
  12 // LWES.net is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // Lesser GNU General Public License for more details.
  16 //
  17 // You should have received a copy of the Lesser GNU General Public License
  18 // along with LWES.net.  If not, see <http://www.gnu.org/licenses/>.
  19 //
  20 namespace Org.Lwes.ESF
  21 {
  22         using System;
  23         using System.Text;
  24
  25         /// <summary>
  26         /// Exception indicating a parse error has occurred.
  27         /// </summary>
  28         [Serializable]
  29         public class ParseException : System.FormatException
  30         {
  31                 #region Fields
  32
  33                 /// <summary>
  34                 /// Value indicating an ErrorPosition is unknown or invalid.
  35                 /// </summary>
  36                 public static readonly int InvalidErrorPosition = -1;
  37
  38                 private int _position = InvalidErrorPosition;
  39
  40                 #endregion Fields
  41
  42                 #region Constructors
  43
  44                 /// <summary>
  45                 /// Creates a new instance.
  46                 /// </summary>
  47                 public ParseException()
  48                 {
  49                 }
  50
  51                 /// <summary>
  52                 /// Creates a new instance initializing the error's message.
  53                 /// </summary>
  54                 /// <param name="msg">the error message</param>
  55                 public ParseException(string msg)
  56                         : base(msg)
  57                 {
  58                 }
  59
  60                 /// <summary>
  61                 /// Creates a new instance initializing the error's message
  62                 /// and indicating the cursor position of the error.
  63                 /// </summary>
  64                 /// <param name="msg">the error message</param>
  65                 /// <param name="cursor">the cursor position of the error</param>
  66                 public ParseException(string msg, Cursor cursor)
  67                         : base(ParseException.MakeErrorMessage(msg, cursor))
  68                 {
  69                         _position = cursor;
  70                 }
  71
  72                 /// <summary>
  73                 /// Creates a new instance indicating the cursor position of the error
  74                 /// and the values that were expected at that position.
  75                 /// </summary>
  76                 /// <param name="curs">the cursor position of the error</param>
  77                 /// <param name="expected">expected values</param>
  78                 public ParseException(Cursor curs, params string[] expected)
  79                         : base(ParseException.MakeErrorMessage(curs, expected))
  80                 {
  81                 }
  82
  83                 #endregion Constructors
  84
  85                 #region Properties
  86
  87                 /// <summary>
  88                 /// Position of the parse error within the parse input.
  89                 /// </summary>
  90                 /// <value>Offset from the beginning parse input where the error occurred.</value>
  91                 public int ErrorPosition
  92                 {
  93                         get { return _position; }
  94                 }
  95
  96                 #endregion Properties
  97
  98                 #region Methods
  99
 100                 private static string MakeErrorMessage(string message, Cursor curs)
 101                 {
 102                         return String.Concat(message, " - at ", curs);
 103                 }
 104
 105                 private static string MakeErrorMessage(Cursor curs, params string[] expected)
 106                 {
 107                         StringBuilder buffer = new StringBuilder(400)
 108                                 .Append("Input cannot be parsed at ").Append(curs.ToString()).Append(": expected ");
 109                         if (expected.Length == 1)
 110                                 buffer.Append(expected[0]);
 111                         else
 112                         {
 113                                 for (int i = 0; i < expected.Length; ++i)
 114                                 {
 115                                         if (i > 0)
 116                                         {
 117                                                 if (i == expected.Length - 1) buffer.Append(" or ");
 118                                                 else buffer.Append(", ");
 119                                         }
 120                                         buffer.Append(expected[i]);
 121                                 }
 122                         }
 123                         return buffer.ToString();
 124                 }
 125
 126                 #endregion Methods
 127         }
 128 }