Improve the evaluate requests (#2583)

Currently it evaluates the given expression in the context of the top most stack frame.
The expression should access to any variables and arguments that are in the scope chain.
Implement the eval_at request with the level of the scope chain as a further argument.

JerryScript-DCO-1.0-Signed-off-by: Robert Sipka rsipka.uszeged@partner.samsung.com

tests/debugger/do_eval_at.cmd

@@ -0,0 +1,20 @@
+eval_at 0
+eval_at 0 b
+n
+eval_at 0 b
+b do_eval_at.js:20
+n
+scopes
+eval_at 0 b
+eval_at 1 b
+eval_at 0 b=20
+eval_at 1 b=100
+n
+eval_at 0 a
+scopes
+eval_at 0 b
+eval_at -1 b
+eval_at 65536 b
+eval_at b
+eval_at 200
+c

tests/debugger/do_eval_at.expected

@@ -0,0 +1,44 @@
+Connecting to: localhost:5001
+Stopped at tests/debugger/do_eval_at.js:15
+(jerry-debugger) eval_at 0
+undefined
+(jerry-debugger) eval_at 0 b
+undefined
+(jerry-debugger) n
+Stopped at tests/debugger/do_eval_at.js:23
+(jerry-debugger) eval_at 0 b
+2
+(jerry-debugger) b do_eval_at.js:20
+Breakpoint 1 at tests/debugger/do_eval_at.js:20 (in f() at line:17, col:1)
+(jerry-debugger) n
+Stopped at breakpoint:1 tests/debugger/do_eval_at.js:20 (in f() at line:17, col:1)
+(jerry-debugger) scopes
+level | type   
+0     | local  
+1     | global 
+(jerry-debugger) eval_at 0 b
+6
+(jerry-debugger) eval_at 1 b
+2
+(jerry-debugger) eval_at 0 b=20
+20
+(jerry-debugger) eval_at 1 b=100
+100
+(jerry-debugger) n
+Stopped at tests/debugger/do_eval_at.js:25
+(jerry-debugger) eval_at 0 a
+23
+(jerry-debugger) scopes
+level | type   
+0     | global 
+(jerry-debugger) eval_at 0 b
+100
+(jerry-debugger) eval_at -1 b
+Error: Invalid scope chain index: -1 (must be between 0 and 65535)
+(jerry-debugger) eval_at 65536 b
+Error: Invalid scope chain index: 65536 (must be between 0 and 65535)
+(jerry-debugger) eval_at b
+Error: invalid literal for int() with base 10: 'b'
+(jerry-debugger) eval_at 200
+Uncaught exception: Error
+(jerry-debugger) c

tests/debugger/do_eval_at.js

@@ -0,0 +1,25 @@
+// Copyright JS Foundation and other contributors, http://js.foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+var b = 2;
+
+function f(a)
+{
+  var b = 6;
+  return a + b;
+}
+
+var a = f(3);
+
+null;

tests/debugger/do_help.expected

@@ -4,9 +4,10 @@ Stopped at tests/debugger/do_help.js:15
 
 Documented commands (type help <topic>):
 ========================================
-abort      bt        display  exception  list      next     s       src      
-b          c         dump     f          memstats  quit     scopes  step     
-backtrace  continue  e        finish     ms        res      scroll  throw    
-break      delete    eval     help       n         restart  source  variables
+abort      c         e          finish    n        s       step     
+b          continue  eval       help      next     scopes  throw    
+backtrace  delete    eval_at    list      quit     scroll  variables
+break      display   exception  memstats  res      source
+bt         dump      f          ms        restart  src   
 
 (jerry-debugger) quit