X-Git-Url: http://nitlanguage.org

diff --git a/src/interpreter/naive_interpreter.nit b/src/interpreter/naive_interpreter.nit
index 66afa45..ac7b970 100644
--- a/src/interpreter/naive_interpreter.nit
+++ b/src/interpreter/naive_interpreter.nit
@@ -23,6 +23,7 @@ private import parser::tables
 import mixin
 import primitive_types
 private import model::serialize_model
+private import frontend::explain_assert_api
 
 redef class ToolContext
 	# --discover-call-trace
@@ -61,7 +62,7 @@ class NaiveInterpreter
 	var modelbuilder: ModelBuilder
 
 	# The main module of the program (used to lookup method)
-	var mainmodule: MModule
+	var mainmodule: MModule is writable
 
 	# The command line arguments of the interpreted program
 	# arguments.first is the program name
@@ -119,7 +120,10 @@ class NaiveInterpreter
 	var escapemark: nullable EscapeMark = null
 
 	# The count of `catch` blocs that have been encountered and can catch an abort
-	var catch_count = 0
+	var catch_count = 0 is writable
+
+	# The last error thrown on abort/runtime error where catch_count > 0
+	var last_error: nullable FatalError = null
 
 	# Is a return or a break or a continue executed?
 	# Use this function to know if you must skip the evaluation of statements
@@ -685,6 +689,15 @@ class NaiveInterpreter
 	var error_instance = new MutableInstance(modelbuilder.model.null_type) is lazy
 end
 
+# A runtime error
+class FatalError
+	# The error message
+	var message: String
+
+	# The problematic node, if any
+	var node: nullable ANode
+end
+
 # An instance represents a value of the executed program.
 abstract class Instance
 	# The dynamic type of the instance
@@ -813,7 +826,7 @@ class InterpreterFrame
 	super Frame
 
 	# Mapping between a variable and the current value
-	private var map: Map[Variable, Instance] = new HashMap[Variable, Instance]
+	var map: Map[Variable, Instance] = new HashMap[Variable, Instance]
 end
 
 redef class ANode
@@ -823,10 +836,11 @@ redef class ANode
 	do
 		# Abort if there is a `catch` block
 		if v.catch_count > 0 then
+			v.last_error = new FatalError(message, self)
 			abort
 		end
 
-		if v.modelbuilder.toolcontext.opt_no_color.value == true then
+		if v.modelbuilder.toolcontext.opt_no_color.value then
 			sys.stderr.write("Runtime error: {message} ({location.file.filename}:{location.line_start})\n")
 		else
 			sys.stderr.write("{location}: Runtime error: {message}\n{location.colored_line("0;31")}\n")
@@ -861,7 +875,10 @@ redef class AMethPropdef
 		return res
 	end
 
-	private fun call_commons(v: NaiveInterpreter, mpropdef: MMethodDef, arguments: Array[Instance], f: Frame): nullable Instance
+	# Execution of the body of the method
+	#
+	# It handle the common special cases: super, intern, extern
+	fun call_commons(v: NaiveInterpreter, mpropdef: MMethodDef, arguments: Array[Instance], f: Frame): nullable Instance
 	do
 		v.frames.unshift(f)
 
@@ -1686,6 +1703,8 @@ redef class AEscapeExpr
 			var i = v.expr(ne)
 			if i == null then return
 			v.escapevalue = i
+		else
+			v.escapevalue = null
 		end
 		v.escapemark = self.escapemark
 	end
@@ -1862,6 +1881,22 @@ redef class AAssertExpr
 		if not cond.is_true then
 			v.stmt(self.n_else)
 			if v.is_escaping then return
+
+			# Explain assert if it fails
+			var explain_assert_str = explain_assert_str
+			if explain_assert_str != null then
+				var i = v.expr(explain_assert_str)
+				if i isa MutableInstance then
+					var res = v.send(v.force_get_primitive_method("to_cstring", i.mtype), [i])
+					if res != null then
+						var val = res.val
+						if val != null then
+							print_error "Runtime assert: {val.to_s}"
+						end
+					end
+				end
+			end
+
 			var nid = self.n_id
 			if nid != null then
 				fatal(v, "Assert '{nid.text}' failed")