Make local variable prefix configurable for display

It's kind of handy to have variable labels tagged.  This makes it
configurable.  The quick-set for Merlin sets it to "]", all others
leave it blank.

SourceGen/AppSettings.cs

@@ -65,6 +65,7 @@ namespace SourceGen {
         public const string FMT_PSEUDO_OP_NAMES = "fmt-pseudo-op-names";
         public const string FMT_CHAR_DELIM = "fmt-char-delim";
         public const string FMT_STRING_DELIM = "fmt-string-delim";
+        public const string FMT_LOCAL_VARIABLE_PREFIX = "fmt-local-variable-prefix";
 
         public const string CLIP_LINE_FORMAT = "clip-line-format";
 
@@ -297,7 +298,8 @@ namespace SourceGen {
         /// Sets a string setting.
         /// </summary>
         /// <param name="name">Setting name.</param>
-        /// <param name="value">Setting value.</param>
+        /// <param name="value">Setting value.  If the value is null, the setting will be
+        ///   removed.</param>
         public void SetString(string name, string value) {
             if (value == null) {
                 mSettings.Remove(name);

SourceGen/AsmGen/GenCommon.cs

@@ -420,6 +420,8 @@ namespace SourceGen.AsmGen {
 
             // Not doing the delimiter patterns here, because what's in the config file is
             // intended for on-screen display, and hence likely to be unsuited for an assembler.
+
+            // Ditto for the local variable prefix.
         }
     }
 }

SourceGen/MainController.cs

@@ -435,11 +435,13 @@ namespace SourceGen {
             mFormatterConfig = new Formatter.FormatConfig();
             AsmGen.GenCommon.ConfigureFormatterFromSettings(AppSettings.Global,
                 ref mFormatterConfig);
-            //mFormatterConfig.mLocalVariableLablePrefix = "\u00a4";  // CURRENCY SIGN
             mFormatterConfig.mEndOfLineCommentDelimiter = ";";
             mFormatterConfig.mFullLineCommentDelimiterBase = ";";
             mFormatterConfig.mBoxLineCommentDelimiter = string.Empty;
 
+            mFormatterConfig.mLocalVariableLablePrefix =
+                settings.GetString(AppSettings.FMT_LOCAL_VARIABLE_PREFIX, string.Empty);
+
             string chrDelCereal = settings.GetString(AppSettings.FMT_CHAR_DELIM, null);
             if (chrDelCereal != null) {
                 mFormatterConfig.mCharDelimiters =

SourceGen/WpfGui/EditAppSettings.xaml

@@ -556,13 +556,21 @@ limitations under the License.
                     </GroupBox>
 
                     <StackPanel DockPanel.Dock="Top" Orientation="Horizontal" Margin="4,16,0,0">
-                        <TextBlock Text="Expression style:"/>
+                        <TextBlock Text="Expression style:" Margin="0,3,0,0"/>
                         <ComboBox Name="expressionStyleComboBox" Width="120" Margin="8,0,0,0"
                                   ItemsSource="{Binding ExpressionStyleItems}" DisplayMemberPath="Name"
                                   IsReadOnly="True"
                                   SelectionChanged="ExpressionStyleComboBox_SelectionChanged"/>
                     </StackPanel>
 
+                    <StackPanel DockPanel.Dock="Top" Orientation="Horizontal" Margin="4,16,0,0">
+                        <TextBlock Text="Local variable prefix:"/>
+                        <TextBox Width="66" MaxLength="8" Margin="8,1,0,0"
+                                 Text="{Binding LocalVarPrefix, UpdateSourceTrigger=PropertyChanged,
+                                    FallbackValue=.placeho}"
+                                 FontFamily="{StaticResource GeneralMonoFont}"/>
+                    </StackPanel>
+
                     <GroupBox DockPanel.Dock="Bottom" Header="Quick Set"
                               Width="400" HorizontalAlignment="Right" Padding="2,4">
                         <DockPanel LastChildFill="False" Margin="4">

SourceGen/WpfGui/EditAppSettings.xaml.cs

@@ -832,6 +832,19 @@ namespace SourceGen.WpfGui {
             get { return sExpStyleItems; }
         }
 
+        public string LocalVarPrefix {
+            get { return mLocalVarPrefix; }
+            set {
+                if (mLocalVarPrefix != value) {
+                    mLocalVarPrefix = value;
+                    OnPropertyChanged();
+                    mSettings.SetString(AppSettings.FMT_LOCAL_VARIABLE_PREFIX, value);
+                    IsDirty = true;
+                }
+            }
+        }
+        private string mLocalVarPrefix;
+
         private void Loaded_DisplayFormat() {
             PopulateWidthDisamSettings();
 
@@ -844,6 +857,9 @@ namespace SourceGen.WpfGui {
 
             // No need to set this to anything specific.
             displayFmtQuickComboBox.SelectedIndex = 0;
+
+            LocalVarPrefix = mSettings.GetString(AppSettings.FMT_LOCAL_VARIABLE_PREFIX,
+                string.Empty);
         }
 
         /// <summary>
@@ -932,12 +948,14 @@ namespace SourceGen.WpfGui {
                 formatConfig.mForceAbsOperandPrefix,
                 formatConfig.mForceLongOperandPrefix);
             SelectExpressionStyle(formatConfig.mExpressionMode);
+            LocalVarPrefix = formatConfig.mLocalVariableLablePrefix;
             // dirty flag set by change watchers if one or more fields have changed
         }
 
         private void QuickFmtDefaultButton_Click(object sender, RoutedEventArgs e) {
             SetWidthDisamSettings(null, "l", "a:", "f:");
             SelectExpressionStyle(ExpressionMode.Common);
+            LocalVarPrefix = string.Empty;
             // dirty flag set by change watchers if one or more fields have changed
         }