add castmode in python and cleaning the castdispatch mechanism

git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk/SWIG@8051 626c5289-ae23-0410-ae9c-e8d60b6d4f22

CHANGES.current

@@ -1,6 +1,46 @@
 Version 1.3.28 (unreleased).
 ===========================
 
+12/23/2005: mmatus
+	    [python] Add the castmode that allows the python
+	    type casting to occurr.
+
+	    For example, if you have 'int foo(int)', now
+	    
+	      class Ai():
+	         def __init__(self,x): 
+		    self.x = x
+	         def __int__(self): 
+		    return self.x
+
+	      foo(1)   // Ok
+	      foo(1.0) // Ok
+	      foo(1.3) // Error
+	      a = Ai(4)
+              foo(ai)  // Ok
+
+            The castmode, which can be enable either with the
+            '-castmode' option or the %module("castmode") option, uses
+            the new cast/rank dispatch mechanism. Hence, now if you
+            have 'int foo(int); int foo(double);', the following works
+            as expected:
+
+	      foo(1)   -> foo(int)
+	      foo(1.0) -> foo(double)
+	      ai = Ai(4)
+	      foo(ai)  -> foo(int)
+
+	    Note1: the 'castmode' could disrupt some specialized
+	    typemaps. In particular, the "implicit.i" library seems to
+	    have problem with the castmode. But besides that one, the
+	    entire test-suite compiles fine with and without the
+	    castmode.
+
+	    Note2: the castmode disables the -fatdispatch option.
+
+	    See the file overload_dispatch_cast_runme.py file for
+	    new cases and examples.
+
 12/22/2005: mmatus
 	    Add the cast and rank mechanism to dispatch overloading
 	    functions. The UTF supports it now, but for each language