Fix #29: Variables should use proper '$' notation

This change adds the dollar sign '$' character to top-level variables that
are retrieved using the Get-Variables command via the DebugService.  This
character is used to refer to variables in PowerShell scripts so we need
to add it to variable names that are returned from the debugging service
for the sake of consistency.

Author: daviwil

src/PowerShellEditorServices/Debugging/VariableDetails.cs

@@ -20,6 +20,11 @@ public class VariableDetails
     {
         #region Fields
 
+        /// <summary>
+        /// Provides a constant for the dollar sign variable prefix string.
+        /// </summary>
+        public const string DollarPrefix = "$";
+
         /// <summary>
         /// Provides a constant for the variable ID of the local variable scope.
         /// </summary>
@@ -79,7 +84,7 @@ public class VariableDetails
         /// The PSVariable instance from which variable details will be obtained.
         /// </param>
         public VariableDetails(PSVariable psVariable)
-            : this(psVariable.Name, psVariable.Value)
+            : this(DollarPrefix + psVariable.Name, psVariable.Value)
         {
         }
 
@@ -105,8 +110,8 @@ public VariableDetails(string name, object value)
         {
             this.valueObject = value;
 
-            this.IsExpandable = GetIsExpandable(value);
             this.Name = name;
+            this.IsExpandable = GetIsExpandable(value);
             this.ValueString =
                 this.IsExpandable == false ?
                     GetValueString(value) :

test/PowerShellEditorServices.Test/Debugging/DebugServiceTests.cs

@@ -177,25 +177,25 @@ await this.debugService.SetBreakpoints(
 
             // TODO: Add checks for correct value strings as well
 
-            var strVar = variables.FirstOrDefault(v => v.Name == "strVar");
+            var strVar = variables.FirstOrDefault(v => v.Name == "$strVar");
             Assert.NotNull(strVar);
             Assert.False(strVar.IsExpandable);
 
-            var objVar = variables.FirstOrDefault(v => v.Name == "objVar");
+            var objVar = variables.FirstOrDefault(v => v.Name == "$objVar");
             Assert.NotNull(objVar);
             Assert.True(objVar.IsExpandable);
 
             var objChildren = debugService.GetVariables(objVar.Id);
             Assert.Equal(2, objChildren.Length);
 
-            var arrVar = variables.FirstOrDefault(v => v.Name == "arrVar");
+            var arrVar = variables.FirstOrDefault(v => v.Name == "$arrVar");
             Assert.NotNull(arrVar);
             Assert.True(arrVar.IsExpandable);
 
             var arrChildren = debugService.GetVariables(arrVar.Id);
             Assert.Equal(4, arrChildren.Length);
 
-            var classVar = variables.FirstOrDefault(v => v.Name == "classVar");
+            var classVar = variables.FirstOrDefault(v => v.Name == "$classVar");
             Assert.NotNull(classVar);
             Assert.True(classVar.IsExpandable);