Derive TextEdit class from Range class

Author: Kapil Borle

Engine/TextEdit.cs

@@ -2,32 +2,33 @@
 
 namespace Microsoft.Windows.PowerShell.ScriptAnalyzer
 {
+    // TODO instead of deriving from Range, make Range a member type.
     /// <summary>
     /// Class to provide information about an edit
     /// </summary>
-    public class TextEdit
+    public class TextEdit : Range
     {
         /// <summary>
         /// 1-based line number on which the text, which needs to be replaced, starts.
         /// </summary>
-        public int StartLineNumber { get; }
+        public int StartLineNumber { get { return this.Start.Line; } }
 
         /// <summary>
         /// 1-based offset on start line at which the text, which needs to be replaced, starts.
         /// This includes the first character of the text.
         /// </summary>
-        public int StartColumnNumber { get; }
+        public int StartColumnNumber { get { return this.Start.Column; } }
 
         /// <summary>
         /// 1-based line number on which the text, which needs to be replace, ends.
         /// </summary>
-        public int EndLineNumber { get; }
+        public int EndLineNumber { get { return this.End.Line; } }
 
         /// <summary>
         /// 1-based offset on end line at which the text, which needs to be replaced, ends.
         /// This offset value is 1 more than the offset of the last character of the text.
         /// </summary>
-        public int EndColumnNumber { get; }
+        public int EndColumnNumber { get { return this.End.Column; } }
 
         /// <summary>
         /// The text that will replace the text bounded by the Line/Column number properties.
@@ -48,47 +49,12 @@ public TextEdit(
             int endLineNumber,
             int endColumnNumber,
             string newText)
+            : base(startLineNumber, startColumnNumber, endLineNumber, endColumnNumber)
         {
-            StartLineNumber = startLineNumber;
-            StartColumnNumber = startColumnNumber;
-            EndLineNumber = endLineNumber;
-            EndColumnNumber = endColumnNumber;
             Text = newText;
-            ThrowIfInvalidArguments();
         }
 
-        private void ThrowIfInvalidArguments()
-        {
-            ThrowIfNull<string>(Text, "text");
 
-            // TODO Localize
-            ThrowIfDecreasing(
-                StartLineNumber,
-                EndLineNumber,
-                "start line number cannot be less than end line number");
-            if (StartLineNumber == EndLineNumber)
-            {
-                ThrowIfDecreasing(
-                    StartColumnNumber,
-                    EndColumnNumber,
-                    "start column number cannot be less than end column number for a one line extent");
-            }
-        }
 
-        private void ThrowIfDecreasing(int start, int end, string message)
-        {
-            if (start > end)
-            {
-                throw new ArgumentException(message);
-            }
-        }
-
-        private void ThrowIfNull<T>(T arg, string argName)
-        {
-            if (arg == null)
-            {
-                throw new ArgumentNullException(argName);
-            }
-        }
     }
 }