anchor.diff:    //     }
     //     var continue_;
     //     bounce() {
  -  //         final c = [[E]];
  +  //         final v = [[E]];
     //         if (v) {
     //             [[S1]];
     //             return continue_();
  
positive.code:           make.block(
                [make.returnStatement(make.functionInvocation(loopName))]),
            make.block(
                [make.returnStatement(make.functionInvocation(breakName))])));
      });
  
      var loopBlock = currentBlock = make.emptyBlock();
  
negative.code:           expr,
            bodyBlock,
            make.block(
                [make.assignmentExpression(
                     make.identifier(breakName), make.booleanLiteral(false)),
                 make.returnStatement(make.functionInvocation(breakName))])));
        });
      } else {
        addStatement(bodyBlock);
  