frog: life is better with colors :)

frog/source.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // TODO(jimhug): This should be an interface to work better with tools.
 /**
  * Represents a file of source code.
  */
 class SourceFile implements Comparable {
   // TODO(terry): This filename for in memory buffer.  May need to rework if
@@ skipping 54 matching lines @@
   }
 
   int getColumn(int line, int position) {
     return position - lineStarts[line];
   }
 
   /**
    * Create a pretty string representation from a character position
    * in the file.
    */
-  String getLocationMessage(String message, int start, [int end, bool includeText=false]) {
+  String getLocationMessage(String message, int start,
+      [int end, bool includeText=false]) {
     var line = getLine(start);
     var column = getColumn(line, start);
 
     var buf = new StringBuffer(
         '${filename}:${line + 1}:${column + 1}: $message');
     if (includeText) {
       buf.add('\n');
       var textLine;
       // +1 for 0-indexing, +1 again to avoid the last line of the file
       if ((line + 2) < _lineStarts.length) {
         textLine = text.substring(_lineStarts[line], _lineStarts[line+1]);
       } else {
         textLine = text.substring(_lineStarts[line]) + '\n';
       }
-      buf.add(textLine);
+
+      int toColumn = Math.min(column + (end-start), textLine.length);
+      if (options.useColors) {
+        buf.add(textLine.substring(0, column));
+        buf.add(_RED_COLOR);
+        buf.add(textLine.substring(column, toColumn));
+        buf.add(_NO_COLOR);
+        buf.add(textLine.substring(toColumn));
+      } else {
+        buf.add(textLine);
+      }
+
       int i = 0;
       for (; i < column; i++) {
         buf.add(' ');
       }
 
-      int toColumn = Math.min(column + (end-start), textLine.length);
-
+      if (options.useColors) buf.add(_RED_COLOR);
       for (; i < toColumn; i++) {
         buf.add('^');
       }
+      if (options.useColors) buf.add(_NO_COLOR);
     }
 
     return buf.toString();
   }
 
   /** Compares two source files. */
   int compareTo(SourceFile other) {
     if (orderInLibrary != null && other.orderInLibrary != null) {
       return orderInLibrary - other.orderInLibrary;
     } else {
@@ skipping 20 matching lines @@
   final int end;
 
   SourceSpan(this.file, this.start, this.end);
 
   /** Returns the source text corresponding to this [Span]. */
   String get text() {
     return file.text.substring(start, end);
   }
 
   toMessageString(String message) {
-    return file.getLocationMessage(message, start, end, true);
+    return file.getLocationMessage(message, start, end: end, includeText: true);
   }
 
   String get locationText() {
     var line = file.getLine(start);
     var column = file.getColumn(line, start);
     return '${file.filename}:${line + 1}:${column + 1}';
   }
 
   /** Compares two source spans by file and position. Handles nulls. */
   int compareTo(SourceSpan other) {
     if (file == other.file) {
       int d = start - other.start;
       return d == 0 ? (end - other.end) : d;
     }
     return file.compareTo(other.file);
   }
 }