diff --git a/.gitignore b/.gitignore
index 6e7b779..95e724d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,7 @@
+__pycache__/
 venv/
+*.pyc
+
 rapport.aux
 rapport.fdb_latexmk
 rapport.fls
diff --git a/examples/simple.spf b/examples/simple.spf
index 61f4245..55cecf7 100644
--- a/examples/simple.spf
+++ b/examples/simple.spf
@@ -2,6 +2,8 @@ texte nom = "anthony";
 entier age = 23;
 booléen majeur = vrai;
 
+booléen ingénieur;
+
 majeur = faux;
 
 afficher nom, age, majeur;
diff --git a/modules/Variables.py b/modules/Variables.py
index 08a073c..c3ff847 100644
--- a/modules/Variables.py
+++ b/modules/Variables.py
@@ -33,7 +33,7 @@ class Variables:
 
 
         def checkType(self, value, typ) -> bool:
-            return type(value) == self.types[typ]
+            return value is None or type(value) == self.types[typ]
 
         def default(self, typ):
             if typ == "entier":
@@ -52,17 +52,27 @@ class Variables:
     def get(self, name):
         assert name in self.variables, "la variable {name} n'éxiste pas"
         if self.trace:
-            print(f"{trace_format}accède {name}{reset_format}", file=sys.stdout)
+            print(f"{trace_format}accède {name}{reset_format}", file=sys.stderr)
         return self.variables[name]
 
     def declare(self, typ, name, value=None):
         assert name not in self.variables, "la variable {name} existe déjà"
         self.variables[name] = self.Variable(typ, value)
         if self.trace:
-            print(f"{trace_format}déclare {name} = {value}{reset_format}", file=sys.stdout)
+            print(f"{trace_format}déclare {name} = {value}{reset_format}", file=sys.stderr)
 
     def assign(self, name, value):
         assert name in self.variables, "la variable n'éxiste pas"
         self.variables[name].set(value)
         if self.trace:
-            print(f"{trace_format}modifie {name} = {value}{reset_format}", file=sys.stdout)
+            print(f"{trace_format}modifie {name} = {value}{reset_format}", file=sys.stderr)
+
+    def dump(self):
+        name_len = max(map(len, self.variables.keys()))
+        var_len = max(map(len,map(str, self.variables.values())))
+        print(f"┌{'─' * name_len}┬{'─' * var_len}┐", file=sys.stderr)
+        print(f"│{'Name':>{name_len}}│{'Value':<{var_len}}│", file=sys.stderr)
+        print(f"├{'─' * name_len}┼{'─' * var_len}┤", file=sys.stderr)
+        for name, var in self.variables.items():
+            print(f"│{name:>{name_len}}│{str(var):<{var_len}}│", file=sys.stderr)
+        print(f"└{'─' * name_len}┴{'─' * var_len}┘", file=sys.stderr)
diff --git a/spf.py b/spf.py
index d076365..2c877d4 100755
--- a/spf.py
+++ b/spf.py
@@ -22,7 +22,7 @@ class SPFInterpreter(lark.visitors.Interpreter):
     def declaration(self, el):
         type = el.children[0].value
         name = el.children[1].value
-        value = self.visit_children(el.children[3])[0] if el.children[2].value == "=" else None
+        value = self.visit_children(el.children[3])[0] if len(el.children) >= 3 else None
         self.variables.declare(type, name, value)
 
     def assignation(self, el):
@@ -70,7 +70,7 @@ def main():
     interpreted = interpreter.visit(parsed)
 
     if args.dump:
-        interpreted.dump()
+        interpreter.dump()
 
 
 if __name__ == "__main__":