diff --git a/src/Makefile b/src/Makefile
index 3996b7212339fddf41964ed11a114236f5c34662..682f9d1f615d5c377f89a80f43e9d53100113213 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -3,6 +3,8 @@ OCAMLMAKEFILE = ./OCamlMakefile
 RESULT=lus2lic
 
 LIBS = str 
+
+ifndef SOURCES
 SOURCES =  \
 	./version.ml \
 	./global.ml \
@@ -37,17 +39,28 @@ SOURCES =  \
 	./lazyCompiler.mli \
 	./compile.ml \
 	./main.ml
+endif
+
+MLONLY_SOURCES=$(filter %.ml %.mll %.mly, $(SOURCES))
+
+# for using the debugger
+debug:
+	mv *.mli mli
+	make MLONLY=yes SOURCES="$(MLONLY_SOURCES)" dc
+	mv mli/* .
 
 
 all: version.ml
 	make bc
 
 
+
 include $(OCAMLMAKEFILE)
 
-MLONLY_SOURCES := $(filter %.ml, $(SOURCES))
 
-tags: $(MLONLY_SOURCES)
+
+
+tags:
 	otags  $(SOURCES)  $(shell ocamlc -where)/*.mli
 
 test: $(RESULT)