diff --git a/debug/tools.py b/debug/tools.py
new file mode 100644
index 0000000..6b7ef2a
--- /dev/null
+++ b/debug/tools.py
@@ -0,0 +1,42 @@
+#!/usr/bin/env python
+# encoding: utf-8
+
+__report_indent = [0]
+def report(fn):
+    """Decorator to print information about a function
+    call for use while debugging.
+    Prints function name, arguments, and call number
+    when the function is called. Prints this information
+    again along with the return value when the function
+    returns.
+    """
+
+    def wrap(*params,**kwargs):
+        call = wrap.callcount = wrap.callcount + 1
+
+        indent = ' ' * __report_indent[0]
+        fc = "%s(%s)" % (fn.__name__, ', '.join(
+            [a.__repr__() for a in params] +
+            ["%s = %s" % (a, repr(b)) for a,b in kwargs.items()]
+        ))
+
+        print( "Call %s%s called [#%s]"
+            % (indent, fc, call))
+        __report_indent[0] += 1
+        ret = fn(*params,**kwargs)
+        __report_indent[0] -= 1
+        try:
+            print(' '*(__report_indent[0]+4), "ret.steps -> ", len(ret.steps))
+        except AttributeError:
+            print(' '*(__report_indent[0]+4), ret, " has no steps")
+        print( "End  %s%s returned %s [#%s]"
+            % (indent, fc, repr(ret), call))
+
+        return ret
+    wrap.callcount = 0
+    return wrap
+
+# -----------------------------
+# Reglages pour 'vim'
+# vim:set autoindent expandtab tabstop=4 shiftwidth=4:
+# cursor: 16 del