Support evaluation of expressions in context of a stack frame

tools/ddbg.dart

 // Copyright (c) 2012, 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.
 
 // Simple interactive debugger shell that connects to the Dart VM's debugger
 // connection port.
 
 import "dart:convert";
 import "dart:io";
 import "dart:async";
@@ skipping 167 matching lines @@
       // TODO(turnidge): Convert all commands to use the Command class.
       print("""
   bt          Show backtrace
   r           Resume execution
   s           Single step
   so          Step over
   si          Step into
   sbp [<file>] <line> Set breakpoint
   rbp <id>    Remove breakpoint with given id
   po <id>     Print object info for given id
+  eval fr  <n> <expr> Evaluate expr on stack frame index n
   eval obj <id> <expr> Evaluate expr on object id
   eval cls <id> <expr> Evaluate expr on class id
   eval lib <id> <expr> Evaluate expr in toplevel of library id
   pl <id> <idx> [<len>] Print list element/slice
   pc <id>     Print class info for given id
   ll          List loaded libraries
   plib <id>   Print library info for given library id
   slib <id> <true|false> Set library id debuggable
   pg <id>     Print all global variables visible within given library id
   ls <lib_id> List loaded scripts in library
@@ skipping 416 matching lines @@
       return;
     }
     var expr = args.getRange(3, args.length).join(" ");
     var target = args[1];
     if (target == "obj") {
       target = "objectId";
     } else if (target == "cls") {
       target = "classId";
     } else if (target == "lib") {
       target = "libraryId";
+    } else if (target == "fr") {
+      target = "frameId";
     } else {
       huh();
       return;
     }
     var cmd = { "id": seqNum,
                 "command": "evaluateExpr",
                 "params": { "isolateId": currentIsolate.id,
                             target: int.parse(args[2]),
                             "expression": expr } };
     sendCmd(cmd).then(showPromptAfter(handleEvalResponse));
@@ skipping 848 matching lines @@
       handleUncaughtError: debuggerError));
 
   zone.run(() {
       parseArgs(args);
       cmdo = new Commando(completer: debuggerCommandCompleter);
       cmdSubscription = cmdo.commands.listen(processCommand,
                                              onError: processError,
                                              onDone: processDone);
     });
 }