Fixes decimal support

Author: AlexCatarino

src/runtime/converter.cs

@@ -75,6 +75,9 @@ internal static Type GetTypeByAlias(IntPtr op)
             if (op == Runtime.PyBoolType)
                 return boolType;
 
+            if (op == Runtime.PyDecimalType)
+                return decimalType;
+
             return null;
         }
 
@@ -105,7 +108,7 @@ internal static IntPtr GetPythonTypeByAlias(Type op)
                 return Runtime.PyBoolType;
 
             if (op == decimalType)
-                return Runtime.PyFloatType;
+                return Runtime.PyDecimalType;
 
             return IntPtr.Zero;
         }

src/runtime/methodbinder.cs

@@ -420,6 +420,12 @@ internal Binding Bind(IntPtr inst, IntPtr args, IntPtr kw, MethodBase info, Meth
                                             typematch = true;
                                             clrtype = pi[n].ParameterType;
                                         }
+                                        // accepts non-decimal numbers in decimal parameters 
+                                        if (underlyingType == typeof(decimal))
+                                        {
+                                            clrtype = pi[n].ParameterType;
+                                            typematch = Converter.ToManaged(op, clrtype, out arg, false);
+                                        }
                                         // this takes care of implicit conversions
                                         var opImplicit = pi[n].ParameterType.GetMethod("op_Implicit", new[] { clrtype });
                                         if (opImplicit != null)

src/runtime/runtime.cs

@@ -296,6 +296,14 @@ internal static void Initialize()
             PyFloatType = PyObject_Type(op);
             XDecref(op);
 
+            IntPtr decimalMod = PyImport_ImportModule("decimal");
+            IntPtr decimalCtor = PyObject_GetAttrString(decimalMod, "Decimal");
+            op = PyObject_CallObject(decimalCtor, IntPtr.Zero);
+            PyDecimalType = PyObject_Type(op);
+            XDecref(op);
+            XDecref(decimalMod);
+            XDecref(decimalCtor);
+
 #if PYTHON3
             PyClassType = IntPtr.Zero;
             PyInstanceType = IntPtr.Zero;
@@ -389,6 +397,7 @@ internal static int AtExit()
         internal static IntPtr PyBoolType;
         internal static IntPtr PyNoneType;
         internal static IntPtr PyTypeType;
+        internal static IntPtr PyDecimalType;
 
 #if PYTHON3
         internal static IntPtr PyBytesType;