diff --git a/commands/FBClassDump.py b/commands/FBClassDump.py
index 3615dd0..c0461a6 100644
--- a/commands/FBClassDump.py
+++ b/commands/FBClassDump.py
@@ -134,7 +134,7 @@ def run(self, arguments, options):
       [dict setObject:types forKey:@"signature"];
     }
     
-    RETURN(dict);
+    RETURN_JSON(dict);
     """
     command = string.Template(tmpString).substitute(block=block)
     json = fb.evaluate(command)
@@ -260,7 +260,7 @@ def getMethods(klass):
       
       [result addObject:m];
     }
-    RETURN(result);
+    RETURN_JSON(result);
   """
   command = string.Template(tmpString).substitute(cls=klass)
   methods = fb.evaluate(command)
@@ -302,10 +302,10 @@ def getProperties(klass):
           NSMutableDictionary *dict = (id)[NSMutableDictionary dictionary];
           
           char *name = (char *)property_getName(props[i]);
-          [dict setObject:(id)[NSString stringWithUTF8String:name] forKey:@"name"];
+          [dict setObject:(id)[NSString stringWithUTF8String:name] forKey:(id)@"name"];
           
           char *attrstr = (char *)property_getAttributes(props[i]);
-          [dict setObject:(id)[NSString stringWithUTF8String:attrstr] forKey:@"attributes_string"];
+          [dict setObject:(id)[NSString stringWithUTF8String:attrstr] forKey:(id)@"attributes_string"];
           
           NSMutableDictionary *attrsDict = (id)[NSMutableDictionary dictionary];
           unsigned int pcount;
@@ -313,13 +313,13 @@ def getProperties(klass):
           for (int i = 0; i < pcount; i++) {
               NSString *name = (id)[NSString stringWithUTF8String:(char *)attrs[i].name];
               NSString *value = (id)[NSString stringWithUTF8String:(char *)attrs[i].value];
-              [attrsDict setObject:value forKey:name];
+              [attrsDict setObject:value forKey:(id)name];
           }
-          [dict setObject:attrsDict forKey:@"attributes"];
+          [dict setObject:attrsDict forKey:(id)@"attributes"];
           
           [result addObject:dict];
       }
-      RETURN(result);
+      RETURN_JSON(result);
     """
   command = string.Template(tmpString).substitute(cls=klass)
   propsJson = fb.evaluate(command)
diff --git a/commands/FBDebugCommands.py b/commands/FBDebugCommands.py
index 4b43c4d..4aedf49 100644
--- a/commands/FBDebugCommands.py
+++ b/commands/FBDebugCommands.py
@@ -7,6 +7,7 @@
 import sys
 import os
 import re
+import string
 
 def lldbcommands():
   return [
@@ -19,6 +20,7 @@ def lldbcommands():
     FBMethodBreakpointDisableCommand(),
     FBHeapFromCommand(),
     FBSequenceCommand(),
+    FBEvaluateFile(),
   ]
 
 class FBWatchInstanceVariableCommand(fb.FBCommand):
@@ -456,3 +458,42 @@ def run(self, arguments, options):
           self.result.SetError(object.GetError())
         self.result.SetStatus(object.GetStatus())
         return
+
+class FBEvaluateFile(fb.FBCommand):
+  def name(self):
+    return 'evalfile'
+
+  def description(self):
+    return 'Run expression from a file.'
+
+  def args(self):
+    return [ fb.FBCommandArgument(arg='file path', type='string', help='file of source code') ]
+
+  def getValue(self, arguments, index):
+    if index >= len(arguments):
+      return None
+    return arguments[index]
+
+  def run(self, arguments, options):
+    file_path = arguments[0].split()[0]
+    if not file_path:
+      print "Error: Missing file"
+      return
+
+    file = open(file_path, 'r')
+    source = file.read()
+    source = string.Template(source).substitute(
+      arg0=self.getValue(arguments, 1),
+      arg1=self.getValue(arguments, 2),
+      arg2=self.getValue(arguments, 3),
+      arg3=self.getValue(arguments, 4)
+    )
+
+    ret = fb.evaluate(source)
+    # if ret is not an address then print it directly
+    if ret[0:2] != '0x':
+      print ret
+    else:
+      command = 'po {}'.format(ret)
+      lldb.debugger.HandleCommand(command)
+
diff --git a/fblldbbase.py b/fblldbbase.py
index dae6897..48bcb1c 100755
--- a/fblldbbase.py
+++ b/fblldbbase.py
@@ -146,17 +146,17 @@ def evaluateCStringExpression(expression, printErrors=True):
     (obj != nil && ((bool)[NSJSONSerialization isValidJSONObject:obj] ||\
     (bool)[obj isKindOfClass:[NSString class]] ||\
     (bool)[obj isKindOfClass:[NSNumber class]]))
-#define RETURN(ret) ({\
+
+#define RETURN_JSON(ret) ({\
     if (!IS_JSON_OBJ(ret)) {\
         (void)[NSException raise:@"Invalid RETURN argument" format:@""];\
     }\
-    NSDictionary *__dict = @{@"return":ret};\
+    NSDictionary *__dict = @{(id)@"return":ret};\
     NSData *__data = (id)[NSJSONSerialization dataWithJSONObject:__dict options:0 error:NULL];\
     NSString *__str = (id)[[NSString alloc] initWithData:__data encoding:4];\
     (char *)[__str UTF8String];})
-#define RETURNCString(ret)\
-    ({NSString *___cstring_ret = [NSString stringWithUTF8String:ret];\
-    RETURN(___cstring_ret);})
+
+#define RETURN(ret) ret
 """
 
 def check_expr(expr):
@@ -176,16 +176,20 @@ def evaluate(expr):
   if not ret.GetError().Success():
     print ret.GetError()
     return None
+
+  isJson = expr.strip().split(';')[-2].find('RETURN_JSON') != -1
+  if not isJson:
+    return ret.GetValue()
+
+  process = lldb.debugger.GetSelectedTarget().GetProcess()
+  error = lldb.SBError()
+  ret = process.ReadCStringFromMemory(int(ret.GetValue(), 16), 2**20, error)
+  if not error.Success():
+    print error
+    return None
   else:
-    process = lldb.debugger.GetSelectedTarget().GetProcess()
-    error = lldb.SBError()
-    ret = process.ReadCStringFromMemory(int(ret.GetValue(), 16), 2**20, error)
-    if not error.Success():
-      print error
-      return None
-    else:
-      ret = json.loads(ret)
-      return ret['return']
+    ret = json.loads(ret)
+    return ret['return']
 
 def currentLanguage():
   return lldb.debugger.GetSelectedTarget().GetProcess().GetSelectedThread().GetSelectedFrame().GetCompileUnit().GetLanguage()