engines: the entry point is `sys.run` or else `sys.main`
[nit.git] / src / debugger.nit
index a8d9317..24df936 100644 (file)
@@ -19,21 +19,121 @@ module debugger
 
 import breakpoint
 intrude import naive_interpreter
+import nitx
+intrude import local_var_init
+intrude import scope
+intrude import toolcontext
+
+redef class Model
+       # Cleans the model to remove a module and what it defines when semantic analysis fails on injected code
+       private fun try_remove_module(m: MModule): Bool
+       do
+               var index = -1
+               for i in [0 .. mmodules.length[ do
+                       if mmodules[i] == m then
+                               index = i
+                               break
+                       end
+               end
+               if index == -1 then return false
+               var mmodule = mmodules[index]
+               mmodules.remove_at(index)
+               for classdef in mmodule.mclassdefs do
+                       var mclass = classdef.mclass
+                       for i in [0 .. mclass.mclassdefs.length[ do
+                               if mclass.mclassdefs[i] == classdef then
+                                       index = i
+                                       break
+                               end
+                       end
+                       mclass.mclassdefs.remove_at(index)
+                       var propdefs = classdef.mpropdefs
+                       for propdef in propdefs do
+                               var prop = propdef.mproperty
+                               for i in [0..prop.mpropdefs.length[ do
+                                       if prop.mpropdefs[i] == propdef then
+                                               index = i
+                                               break
+                                       end
+                               end
+                               prop.mpropdefs.remove_at(index)
+                       end
+               end
+               return true
+       end
+end
+
+redef class ScopeVisitor
+
+       redef init(toolcontext)
+       do
+               super
+               if toolcontext.dbg != null then
+                       var localvars = toolcontext.dbg.frame.map
+                       for i in localvars.keys do
+                               scopes.first.variables[i.to_s] = i
+                       end
+               end
+       end
+
+end
+
+redef class LocalVarInitVisitor
+       redef fun mark_is_unset(node: AExpr, variable: nullable Variable)
+       do
+               super
+               if toolcontext.dbg != null then
+                       var varname = variable.to_s
+                       var instmap = toolcontext.dbg.frame.map
+                       for i in instmap.keys do
+                               if i.to_s == varname then
+                                       mark_is_set(node, variable)
+                               end
+                       end
+               end
+       end
+
+end
 
 redef class ToolContext
+       private var dbg: nullable Debugger = null
+
+       private var had_error: Bool = false
+
+       redef fun check_errors
+       do
+               if dbg == null then
+                       super
+               else
+                       if messages.length > 0 then
+                               message_sorter.sort(messages)
+
+                               for m in messages do
+                                       if m.text.search("Warning") == null then had_error = true
+                                       sys.stderr.write("{m.to_color_string}\n")
+                               end
+                       end
+
+                       messages.clear
+               end
+       end
+
        # -d
        var opt_debugger_mode: OptionBool = new OptionBool("Launches the target program with the debugger attached to it", "-d")
+       # -c
+       var opt_debugger_autorun: OptionBool = new OptionBool("Launches the target program with the interpreter, such as when the program fails, the debugging prompt is summoned", "-c")
 
        redef init
        do
                super
                self.option_context.add_option(self.opt_debugger_mode)
+               self.option_context.add_option(self.opt_debugger_autorun)
        end
 end
 
 redef class ModelBuilder
-       # Execute the program from the entry point (Sys::main) of the `mainmodule'
-       # `arguments' are the command-line arguments in order
+       # Execute the program from the entry point (Sys::main) of the `mainmodule`
+       # `arguments` are the command-line arguments in order
        # REQUIRE that:
        #   1. the AST is fully loaded.
        #   2. the model is fully built.
@@ -50,9 +150,23 @@ redef class ModelBuilder
                var time1 = get_time
                self.toolcontext.info("*** END INTERPRETING: {time1-time0} ***", 2)
        end
+
+       fun run_debugger_autorun(mainmodule: MModule, arguments: Array[String])
+       do
+               var time0 = get_time
+               self.toolcontext.info("*** START INTERPRETING ***", 1)
+
+               var interpreter = new Debugger(self, mainmodule, arguments)
+               interpreter.autocontinue = true
+
+               init_naive_interpreter(interpreter, mainmodule)
+
+               var time1 = get_time
+               self.toolcontext.info("*** END INTERPRETING: {time1-time0} ***", 2)
+       end
 end
 
-# The class extending NaiveInterpreter by adding debugging methods
+# The class extending `NaiveInterpreter` by adding debugging methods
 class Debugger
        super NaiveInterpreter
 
@@ -79,6 +193,23 @@ class Debugger
        # Aliases hashmap (maps an alias to a variable name)
        var aliases = new HashMap[String, String]
 
+       # Set containing all the traced variables and their related frame
+       private var traces = new HashSet[TraceObject]
+
+       # Map containing all the positions for the positions of the arguments traced
+       # In a function call
+       private var fun_call_arguments_positions = new HashMap[Int, TraceObject]
+
+       # Triggers the remapping of a trace object in the local context after a function call
+       var aftermath = false
+
+       # Used to prevent the case when the body of the function called is empty
+       # If it is not, then, the remapping won't be happening
+       var frame_count_aftermath = 1
+
+       # Auto continues the execution until the end or until an error is encountered
+       var autocontinue = false
+
        #######################################################################
        ##                  Execution of statement function                  ##
        #######################################################################
@@ -92,32 +223,148 @@ class Debugger
                var old = frame.current_node
                frame.current_node = n
 
-               if not n isa ABlockExpr then
-                       steps_fun_call(n)
+               if sys.stdin.poll_in then process_debug_command(gets)
+
+               if not self.autocontinue then
+                       if not n isa ABlockExpr then
+                               steps_fun_call(n)
+
+                               breakpoint_check(n)
+
+                               check_funcall_and_traced_args(n)
 
-                       breakpoint_check(n)
+                               remap(n)
+
+                               check_if_vars_are_traced(n)
+                       end
                end
 
                n.stmt(self)
                frame.current_node = old
        end
 
+       # Does the same as an usual send, except it will modify the call chain on the first call when injecting code at Runtime using the debugger.
+       # Instead of creating a pristine Frame, it will copy the actual values of the frame, and re-inject them after execution in the current context.
+       fun rt_send(mproperty: MMethod, args: Array[Instance]): nullable Instance
+       do
+               var recv = args.first
+               var mtype = recv.mtype
+               var ret = send_commons(mproperty, args, mtype)
+               if ret != null then return ret
+               var propdef = mproperty.lookup_first_definition(self.mainmodule, mtype)
+               return self.rt_call(propdef, args)
+       end
+
+       # Same as a regular call but for a runtime injected module
+       #
+       fun rt_call(mpropdef: MMethodDef, args: Array[Instance]): nullable Instance
+       do
+               args = call_commons(mpropdef, args)
+               return rt_call_without_varargs(mpropdef, args)
+       end
+
+       # Common code to call and this function
+       #
+       # Call only executes the variadic part, this avoids
+       # double encapsulation of variadic parameters into an Array
+       fun rt_call_without_varargs(mpropdef: MMethodDef, args: Array[Instance]): nullable Instance
+       do
+               if self.modelbuilder.toolcontext.opt_discover_call_trace.value and not self.discover_call_trace.has(mpropdef) then
+                       self.discover_call_trace.add mpropdef
+                       self.debug("Discovered {mpropdef}")
+               end
+               assert args.length == mpropdef.msignature.arity + 1 else debug("Invalid arity for {mpropdef}. {args.length} arguments given.")
+
+               # Look for the AST node that implements the property
+               var mproperty = mpropdef.mproperty
+               if self.modelbuilder.mpropdef2npropdef.has_key(mpropdef) then
+                       var npropdef = self.modelbuilder.mpropdef2npropdef[mpropdef]
+                       self.parameter_check(npropdef, mpropdef, args)
+                       if npropdef isa AMethPropdef then
+                               return npropdef.rt_call(self, mpropdef, args)
+                       else
+                               print "Error, invalid propdef to call at runtime !"
+                               return null
+                       end
+               else if mproperty.name == "init" then
+                       var nclassdef = self.modelbuilder.mclassdef2nclassdef[mpropdef.mclassdef]
+                       self.parameter_check(nclassdef, mpropdef, args)
+                       return nclassdef.call(self, mpropdef, args)
+               else
+                       fatal("Fatal Error: method {mpropdef} not found in the AST")
+                       abort
+               end
+       end
+
+       # Evaluates dynamically a snippet of Nit code
+       # `nit_code` : Nit code to be executed
+       fun eval(nit_code: String)
+       do
+               var local_toolctx = modelbuilder.toolcontext
+               local_toolctx.dbg = self
+               var e = local_toolctx.parse_something(nit_code)
+               if e isa ABlockExpr then
+                       nit_code = "module rt_module\n" + nit_code
+                       e = local_toolctx.parse_something(nit_code)
+               end
+               if e isa AExpr then
+                       nit_code = "module rt_module\nprint " + nit_code
+                       e = local_toolctx.parse_something(nit_code)
+               end
+               if e isa AModule then
+                       local_toolctx.had_error = false
+                       modelbuilder.load_rt_module(self.mainmodule, e, "rt_module")
+                       local_toolctx.run_phases([e])
+                       if local_toolctx.had_error then
+                               modelbuilder.model.try_remove_module(e.mmodule.as(not null))
+                               local_toolctx.dbg = null
+                               return
+                       end
+                       var mmod = e.mmodule
+                       if mmod != null then
+                               self.mainmodule = mmod
+                               var local_classdefs = mmod.mclassdefs
+                               var sys_type = mmod.sys_type
+                               if sys_type == null then
+                                       print "Fatal error, cannot find Class Sys !\nAborting"
+                                       abort
+                               end
+                               var mobj = new MutableInstance(sys_type)
+                               init_instance(mobj)
+                               var initprop = mmod.try_get_primitive_method("init", sys_type.mclass)
+                               if initprop != null then
+                                       self.send(initprop, [mobj])
+                               end
+                               var mainprop = mmod.try_get_primitive_method("run", sys_type.mclass) or else
+                                       mmod.try_get_primitive_method("main", sys_type.mclass)
+                               if mainprop != null then
+                                       self.rt_send(mainprop, [mobj])
+                               end
+                       else
+                               print "Error while loading_rt_module"
+                       end
+               else
+                       print "Error when parsing, e = {e.class_name}"
+               end
+               local_toolctx.dbg = null
+       end
+
        # Encpasulates the behaviour for step over/out
        private fun steps_fun_call(n: AExpr)
        do
                if self.stop_after_step_over_trigger then
                        if self.frames.length <= self.step_stack_count then
                                n.debug("Execute stmt {n.to_s}")
-                               while process_debug_command(gets) do end
+                               while read_cmd do end
                        end
                else if self.stop_after_step_out_trigger then
                        if frames.length < self.step_stack_count then
                                n.debug("Execute stmt {n.to_s}")
-                               while process_debug_command(gets) do end
+                               while read_cmd do end
                        end
                else if step_in_trigger then
                        n.debug("Execute stmt {n.to_s}")
-                       while process_debug_command(gets) do end
+                       while read_cmd do end
                end
        end
 
@@ -140,7 +387,66 @@ class Debugger
                        end
 
                        n.debug("Execute stmt {n.to_s}")
-                       while process_debug_command(gets) do end
+                       while read_cmd do end
+               end
+       end
+
+       # Check if a variable of current expression is traced
+       # Then prints and/or breaks for command prompt
+       private fun check_if_vars_are_traced(n: AExpr)
+       do
+               var identifiers_in_instruction = get_identifiers_in_current_instruction(n.location.text)
+
+               for i in identifiers_in_instruction do
+                       var variable = seek_variable(i, frame)
+                       for j in self.traces do
+                               if j.is_variable_traced_in_frame(i, frame) then
+                                       n.debug("Traced variable {i} used")
+                                       if j.break_on_encounter then while read_cmd do end
+                                       break
+                               end
+                       end
+               end
+       end
+
+       # Function remapping all the traced objects to match their name in the local context
+       private fun remap(n: AExpr)
+       do
+               if self.aftermath then
+
+                       # Trace every argument variable pre-specified
+                       if self.frame_count_aftermath < frames.length and fun_call_arguments_positions.length > 0 then
+
+                               var ids_in_fun_def = get_identifiers_in_current_instruction(get_function_arguments(frame.mpropdef.location.text))
+
+                               for i in fun_call_arguments_positions.keys do
+                                       self.fun_call_arguments_positions[i].add_frame_variable(frame, ids_in_fun_def[i])
+                               end
+                       end
+
+                       self.aftermath = false
+               end
+       end
+
+       # If the current instruction is a function call
+       # We analyse its signature and the position of traced arguments if the call
+       # For future remapping when inside the function
+       private fun check_funcall_and_traced_args(n: AExpr) do
+               # If we have a function call, we need to see if any of the arguments is traced (including the caller)
+               # if it is, next time we face an instruction, we'll trace the local version on the traced variable in the next frame
+               if n isa ACallExpr then
+                       self.aftermath = true
+                       self.frame_count_aftermath = frames.length
+                       fun_call_arguments_positions.clear
+                       var fun_arguments = get_identifiers_in_current_instruction(get_function_arguments(n.location.text))
+
+                       for i in self.traces do
+                               for j in [0 .. fun_arguments.length - 1] do
+                                       if i.is_variable_traced_in_frame(fun_arguments[j],frame) then
+                                               fun_call_arguments_positions[j] = i
+                                       end
+                               end
+                       end
                end
        end
 
@@ -148,20 +454,20 @@ class Debugger
        ##                   Processing commands functions                   ##
        #######################################################################
 
+       fun read_cmd: Bool
+       do
+               printn "> "
+               return process_debug_command(gets)
+       end
+
        # Takes a user command as a parameter
        #
        # Returns a boolean value, representing whether or not to
        # continue reading commands from the console input
        fun process_debug_command(command:String): Bool
        do
-               # For lisibility
-               print "\n"
-
-               # Kills the current program
-               if command == "kill" then
-                       abort
                # Step-out command
-               else if command == "finish"
+               if command == "finish"
                then
                        return step_out
                # Step-in command
@@ -171,9 +477,30 @@ class Debugger
                # Step-over command
                else if command == "n" then
                        return step_over
+               # Opens a new NitIndex prompt on current model
+               else if command == "nitx" then
+                       new NitIndex.with_infos(modelbuilder, self.mainmodule).prompt
+                       return true
                # Continues execution until the end
                else if command == "c" then
                        return continue_exec
+               else if command == "nit" then
+                       printn "$~> "
+                       command = gets
+                       var nit_buf = new FlatBuffer
+                       while not command == ":q" do
+                               nit_buf.append(command)
+                               nit_buf.append("\n")
+                               printn "$~> "
+                               command = gets
+                       end
+                       step_in
+                       eval(nit_buf.to_s)
+               else if command == "quit" then
+                       exit(0)
+               else if command == "abort" then
+                       print stack_trace
+                       exit(0)
                else
                        var parts_of_command = command.split_with(' ')
                        # Shows the value of a variable in the current frame
@@ -197,9 +524,14 @@ class Debugger
                        # Modifies the value of a variable in the current frame
                        else if parts_of_command.length >= 3 and parts_of_command[1] == "=" then
                                process_mod_function(parts_of_command)
-                       # Lists all the commands available
+                       # Traces the modifications on a variable
+                       else if parts_of_command.length >= 2 and parts_of_command[0] == "trace" then
+                               process_trace_command(parts_of_command)
+                       # Untraces the modifications on a variable
+                       else if parts_of_command.length == 2 and parts_of_command[0] == "untrace" then
+                               process_untrace_command(parts_of_command)
                        else
-                               list_commands
+                               print "Unknown command \"{command}\""
                        end
                end
                return true
@@ -257,14 +589,15 @@ class Debugger
 
                        var keys = map_of_instances.iterator
 
-                       print "Variables collection : \n"
+                       var self_var = seek_variable("self", frame)
+                       print "self: {self_var.to_s}"
 
                        for instance in map_of_instances.keys do
-                               print "Variable {instance.to_s}, Instance {map_of_instances[instance].to_s}"
+                               print "{instance.to_s}: {map_of_instances[instance].to_s}"
                        end
-
-                       print "\nEnd of current instruction \n"
-               else if parts_of_command[1].has('[') and parts_of_command[1].has(']') then
+               else if parts_of_command[1] == "stack" then
+                       print self.stack_trace
+               else if parts_of_command[1].chars.has('[') and parts_of_command[1].chars.has(']') then
                        process_array_command(parts_of_command)
                else
                        var instance = seek_variable(get_real_variable_name(parts_of_command[1]), frame)
@@ -284,8 +617,6 @@ class Debugger
                var bp = get_breakpoint_from_command(parts_of_command)
                if bp != null then
                        place_breakpoint(bp)
-               else
-                       list_commands
                end
        end
 
@@ -308,15 +639,13 @@ class Debugger
                        remove_breakpoint(self.curr_file, parts_of_command[1].to_i)
                else if parts_of_command.length >= 3 and parts_of_command[2].is_numeric then
                        remove_breakpoint(parts_of_command[1], parts_of_command[2].to_i)
-               else
-                       list_commands
                end
        end
 
        # Processes an array print command
        fun process_array_command(parts_of_command: Array[String])
        do
-               var index_of_first_brace = parts_of_command[1].index_of('[')
+               var index_of_first_brace = parts_of_command[1].chars.index_of('[')
                var variable_name = get_real_variable_name(parts_of_command[1].substring(0,index_of_first_brace))
                var braces = parts_of_command[1].substring_from(index_of_first_brace)
 
@@ -371,6 +700,192 @@ class Debugger
                end
        end
 
+       # Processes the untrace variable command
+       #
+       # Command pattern : "untrace variable"
+       fun process_untrace_command(parts_of_command: Array[String])
+       do
+               var variable_name = get_real_variable_name(parts_of_command[1])
+               if untrace_variable(variable_name) then
+                       print "Untraced variable {parts_of_command[1]}"
+               else
+                       print "{parts_of_command[1]} is not traced"
+               end
+       end
+
+       # Processes the trace variable command
+       #
+       # Command pattern : "trace variable [break/print]"
+       fun process_trace_command(parts_of_command: Array[String])
+       do
+               var variable_name = get_real_variable_name(parts_of_command[1])
+               var breaker:Bool
+
+               if seek_variable(variable_name, frame) == null then
+                       print "Cannot find a variable called {parts_of_command[1]}"
+                       return
+               end
+
+               if parts_of_command.length == 3 then
+                       if parts_of_command[2] == "break" then
+                               breaker = true
+                       else
+                               breaker = false
+                       end
+               else
+                       breaker = false
+               end
+
+               trace_variable(variable_name, breaker)
+
+               print "Successfully tracing {parts_of_command[1]}"
+       end
+
+       #######################################################################
+       ##                    Trace Management functions                     ##
+       #######################################################################
+
+       # Effectively untraces the variable called *variable_name*
+       #
+       # Returns true if the variable exists, false otherwise
+       private fun untrace_variable(variable_name: String): Bool
+       do
+               var to_remove: nullable TraceObject = null
+               for i in self.traces do
+                       if i.is_variable_traced_in_frame(variable_name, frame) then
+                               to_remove = i
+                       end
+               end
+
+               if to_remove != null then
+                       self.traces.remove(to_remove)
+                       return true
+               else
+                       return false
+               end
+       end
+
+       # Effectively traces the variable *variable_name* either in print or break mode depending on the value of breaker (break if true, print if false)
+       #
+       private fun trace_variable(variable_name: String, breaker: Bool)
+       do
+               for i in self.traces do
+                       if i.is_variable_traced_in_frame(variable_name, frame) then
+                               print "This variable is already traced"
+                               return
+                       end
+               end
+
+               var trace_object: TraceObject
+
+               if breaker then
+                       trace_object = new TraceObject(true)
+               else
+                       trace_object = new TraceObject(false)
+               end
+
+               # We trace the current variable found for the current frame
+               trace_object.add_frame_variable(self.frame, variable_name)
+
+               var position_of_variable_in_arguments = get_position_of_variable_in_arguments(frame, variable_name)
+
+               # Start parsing the frames starting with the parent of the current one, until the highest
+               # When the variable traced is declared locally, the loop stops
+               for i in [1 .. frames.length-1] do
+
+                       # If the variable was reported to be an argument of the previous frame
+                       if position_of_variable_in_arguments != -1 then
+
+                               var local_name = get_identifiers_in_current_instruction(get_function_arguments(frames[i].current_node.location.text))[position_of_variable_in_arguments]
+
+                               position_of_variable_in_arguments = get_position_of_variable_in_arguments(frames[i], local_name)
+
+                               trace_object.add_frame_variable(frames[i], local_name)
+                       else
+                               break
+                       end
+               end
+
+               self.traces.add(trace_object)
+       end
+
+       # If the variable *variable_name* is an argument of the function being executed in the frame *frame*
+       # The function returns its position in the arguments
+       # Else, it returns -1
+       private fun get_position_of_variable_in_arguments(frame: Frame, variable_name: String): Int
+       do
+               var identifiers = get_identifiers_in_current_instruction(get_function_arguments(frame.mpropdef.location.text))
+               for i in [0 .. identifiers.length-1] do
+                       # If the current traced variable is an argument of the current function, we trace its parent (at least)
+                       if identifiers[i] == variable_name then return i
+               end
+               return -1
+       end
+
+       # Gets all the identifiers of an instruction (uses the rules of Nit as of Mar 05 2013)
+       #
+       fun get_identifiers_in_current_instruction(instruction: Text): Array[String]
+       do
+               var result_array = new Array[String]
+               var instruction_buffer = new FlatBuffer
+
+               var trigger_char_escape = false
+               var trigger_string_escape = false
+               var trigger_concat_in_string = false
+
+               for i in instruction.chars do
+                       if trigger_char_escape then
+                               if i == '\'' then trigger_char_escape = false
+                       else if trigger_string_escape then
+                               if i == '{' then
+                                       trigger_concat_in_string = true
+                                       trigger_string_escape = false
+                               else if i == '\"' then trigger_string_escape = false
+                       else
+                               if i.is_alphanumeric or i == '_' then
+                                       instruction_buffer.add(i)
+                               else if i == '.' then
+                                       if instruction_buffer.is_numeric or (instruction_buffer.chars[0] >= 'A' and instruction_buffer.chars[0] <= 'Z') then
+                                               instruction_buffer.clear
+                                       else
+                                               result_array.push(instruction_buffer.to_s)
+                                               instruction_buffer.add(i)
+                                       end
+                               else if i == '\'' then
+                                       trigger_char_escape = true
+                               else if i == '\"' then
+                                       trigger_string_escape = true
+                               else if i == '}' then
+                                       trigger_concat_in_string = false
+                                       trigger_string_escape = true
+                               else
+                                       if instruction_buffer.length > 0 and not instruction_buffer.is_numeric and not (instruction_buffer.chars[0] >= 'A' and instruction_buffer.chars[0] <= 'Z') then result_array.push(instruction_buffer.to_s)
+                                       instruction_buffer.clear
+                               end
+                       end
+               end
+
+               if instruction_buffer.length > 0 and not instruction_buffer.is_numeric and not (instruction_buffer.chars[0] >= 'A' and instruction_buffer.chars[0] <= 'Z') then result_array.push(instruction_buffer.to_s)
+
+               return result_array
+       end
+
+       # Takes a function call or declaration and strips all but the arguments
+       #
+       fun get_function_arguments(function: Text): String
+       do
+               var buf = new FlatBuffer
+               var trigger_copy = false
+
+               for i in function.chars do
+                       if i == ')' then break
+                       if trigger_copy then buf.add(i)
+                       if i == '(' then trigger_copy = true
+               end
+
+               return buf.to_s
+       end
+
        #######################################################################
        ##                    Alias management functions                     ##
        #######################################################################
@@ -395,7 +910,7 @@ class Debugger
        fun get_real_variable_name(name: String): String
        do
                var explode_string = name.split_with(".")
-               var final_string = new Buffer
+               var final_string = new FlatBuffer
                for i in explode_string do
                        var alias_resolved = get_variable_name_by_alias(i)
                        if alias_resolved != null then
@@ -419,14 +934,16 @@ class Debugger
        fun print_instance(instance: Instance)
        do
                if instance isa MutableInstance then
-                       var attributes = instance.attributes
-                       print "Object : {instance}"
+                       print "\{"
+                       print "\ttype : {instance},"
 
-                       for current_attribute in attributes.keys do
-                               print "Attribute : {current_attribute.to_s} \nValeur : {attributes[current_attribute].to_s}"
-                       end
+                       printn("\t")
+
+                       print instance.attributes.join(",\n\t"," : ")
+
+                       print "\}"
                else
-                       print "Found variable {instance}"
+                       print "{instance}"
                end
        end
 
@@ -582,8 +1099,8 @@ class Debugger
        # Returns an array containing all the indexes demanded
        fun process_index(index_string: String): nullable Array[Int]
        do
-               var from_end_index = index_string.index_of('.')
-               var to_start_index = index_string.last_index_of('.')
+               var from_end_index = index_string.chars.index_of('.')
+               var to_start_index = index_string.chars.last_index_of('.')
 
                if from_end_index != -1 and to_start_index != -1 then
                        var index_from_string = index_string.substring(0,from_end_index)
@@ -639,7 +1156,7 @@ class Debugger
        # Returns an array containing their content
        fun remove_braces(braces: String): nullable Array[String]
        do
-               var buffer = new Buffer
+               var buffer = new FlatBuffer
 
                var result_array = new Array[String]
 
@@ -648,7 +1165,7 @@ class Debugger
 
                var last_was_opening_bracket = false
 
-               for i in braces do
+               for i in braces.chars do
                        if i == '[' then
                                if last_was_opening_bracket then
                                        return null
@@ -705,8 +1222,6 @@ class Debugger
                then
                        bp.set_max_breaks(1)
                        place_breakpoint(bp)
-               else
-                       list_commands
                end
        end
 
@@ -828,7 +1343,7 @@ class Debugger
        fun get_char(value: String): nullable Instance
        do
                if value.length >= 1 then
-                       return char_instance(value[0])
+                       return char_instance(value.chars[0])
                else
                        return null
                end
@@ -847,30 +1362,83 @@ class Debugger
                end
        end
 
-       #######################################################################
-       ##                     Command listing function                      ##
-       #######################################################################
+end
+
+redef class AMethPropdef
 
-       # Lists the commands available when using the debugger
-       fun list_commands
-       do
-               print "\nCommand not recognized\n"
-               print "Commands accepted : \n"
-               print "[break/b] line : Adds a breakpoint on line *line_nb* of the current file\n"
-               print "[break/b] file_name line_nb : Adds a breakpoint on line *line_nb* of file *file_name* \n"
-               print "[p/print] variable : [p/print] * shows the status of all the variables\n"
-               print "[p/print] variable[i] : Prints the value of the variable contained at position *i* in SequenceRead collection *variable*\n"
-               print "[p/print] variable[i..j]: Prints the value of all the variables contained between positions *i* and *j* in SequenceRead collection *variable*\n"
-               print "Note : The arrays can be multi-dimensional (Ex : variable[i..j][k] will print all the values at position *k* of all the SequenceRead collections contained between positions *i* and *j* in SequenceRead collection *variable*)\n"
-               print "s : steps in on the current function\n"
-               print "n : steps-over the current instruction\n"
-               print "finish : steps out of the current function\n"
-               print "variable as alias : Adds an alias called *alias* for the variable *variable*"
-               print "An alias can reference another alias\n"
-               print "variable = value : Sets the value of *variable* to *value*\n"
-               print "[d/delete] line_nb : Removes a breakpoint on line *line_nb* of the current file \n"
-               print "[d/delete] file_name line_nb : Removes a breakpoint on line *line_nb* of file *file_name* \n"
-               print "kill : kills the current program (Exits with an error and stack trace)\n"
+       # Same as call except it will copy local variables of the parent frame to the frame defined in this call.
+       # Not supposed to be used by anyone else than the Debugger.
+       private fun rt_call(v: Debugger, mpropdef: MMethodDef, args: Array[Instance]): nullable Instance
+       do
+               var f = new Frame(self, self.mpropdef.as(not null), args)
+               var curr_instances = v.frame.map
+               for i in curr_instances.keys do
+                       f.map[i] = curr_instances[i]
+               end
+               call_commons(v,mpropdef,args,f)
+               var currFra = v.frames.shift
+               for i in curr_instances.keys do
+                       if currFra.map.keys.has(i) then
+                               curr_instances[i] = currFra.map[i]
+                       end
+               end
+               if v.returnmark == f then
+                       v.returnmark = null
+                       var res = v.escapevalue
+                       v.escapevalue = null
+                       return res
+               end
+               return null
+
+       end
+end
+
+# Traces the modifications of an object linked to a certain frame
+private class TraceObject
+
+       # Map of the local names bound to a frame
+       var trace_map: HashMap[Frame, String]
+       # Decides if breaking or printing statement when the variable is encountered
+       var break_on_encounter: Bool
+
+       init(break_on_encounter: Bool)
+       do
+               trace_map = new HashMap[Frame, String]
+               self.break_on_encounter = break_on_encounter
+       end
+
+       # Adds the local alias for a variable and the frame bound to it
+       fun add_frame_variable(frame: Frame, variable_name: String)
+       do
+               self.trace_map[frame] = variable_name
        end
 
+       # Checks if the prompted variable is traced in the specified frame
+       fun is_variable_traced_in_frame(variable_name: String, frame: Frame): Bool
+       do
+               if self.trace_map.has_key(frame) then
+                       if self.trace_map[frame] == variable_name then
+                               return true
+                       end
+               end
+
+               return false
+       end
+
+end
+
+redef class ANode
+
+       # Breaks automatically when encountering an error
+       # Permits the injunction of commands before crashing
+       redef private fun fatal(v: NaiveInterpreter, message: String)
+       do
+               if v isa Debugger then
+                       print "An error was encountered, the program will stop now."
+                       self.debug(message)
+                       while v.process_debug_command(gets) do end
+               end
+
+               super
+       end
 end