/** Creates a new StackFrame. */
 private StackFrame(Context cx, Dim dim, FunctionSource fsource) {
   this.dim = dim;
   this.contextData = ContextData.get(cx);
   this.fsource = fsource;
   this.breakpoints = fsource.sourceInfo().breakpoints;
   this.lineNumber = fsource.firstLine();
 }
 /** Returns the source URL. */
 public String getUrl() {
   return fsource.sourceInfo().url();
 }
 /** Returns the SourceInfo object for the function. */
 public SourceInfo sourceInfo() {
   return fsource.sourceInfo();
 }