Naive_interpreter : Adding object inspector

lib/core/kernel.nit

@@ -222,6 +222,11 @@ interface Object
 	#
 	# Without redefinition, `hash` is based on the `object_id` of the instance.
 	fun hash: Int do return object_id
+
+	# Method catch by the interpreter to display the object value and to start the step-by-step execution.
+	#
+	# This method MUST not be used by programs, it is here for debugging in the interpreter
+	fun inspect_o is intern
 end
 
 # The main class of the program.

share/man/nit.md

@@ -86,6 +86,11 @@ Each time a method is invoked for the first time, its information is printed on
 
 This option helps the user to have a simplified but humanly readable overview of the behavior of a particular program execution.
 
+### `--break`
+Start the program to indicate the breakpoints for the interpretation.
+
+Print the menu to add or remove some breakpoint
+
 ## DEBUGGER OPTIONS
 
 ### `-d`

src/interpreter/interpreter.nit

@@ -15,5 +15,5 @@
 # Interpretation of Nit programs
 module interpreter
 
-import naive_interpreter
+import step_interpreter
 import dynamic_loading_ffi

src/interpreter/naive_interpreter.nit

@@ -27,11 +27,14 @@ private import frontend::explain_assert_api
 redef class ToolContext
 	# --discover-call-trace
 	var opt_discover_call_trace = new OptionBool("Trace calls of the first invocation of methods", "--discover-call-trace")
+	# --stop-at
+	var opt_stop = new OptionBool("Start the program to indicate the breakpoints for the interpretation","--break")
 
 	redef init
 	do
 		super
 		self.option_context.add_option(self.opt_discover_call_trace)
+		self.option_context.add_option(self.opt_stop)
 	end
 end
 
@@ -446,13 +449,33 @@ class NaiveInterpreter
 		return f.map[v]
 	end
 
+	# Retrieve the value of the variable in the current frame
+	fun read_null_variable(v: Variable):nullable Instance
+	do
+		var f = frames.first.as(InterpreterFrame)
+		if f.map.has_key(v) then return f.map[v]
+		return null
+	end
+
 	# Assign the value of the variable in the current frame
 	fun write_variable(v: Variable, value: Instance)
 	do
 		var f = frames.first.as(InterpreterFrame)
 		f.map[v] = value
 	end
 
+	# Retrieve the variable of the Instance in the current frame
+	fun read_instance(i: nullable Instance): nullable Variable
+	do
+		if i != null then
+			var f = frames.first.as(InterpreterFrame)
+			for key, value in f.map do
+				if value == i then return key
+			end
+		end
+		return null
+	end
+
 	# Store known methods, used to trace methods as they are reached
 	var discover_call_trace: Set[MMethodDef] = new HashSet[MMethodDef]