import ROOT

# When iterating over an EventFile, the Evt object is actually 
# the same one. It just gets filled by root each time...
# But root does not fill/clear the __dict__, so we intercept it
# and do it from python

try :
    orgnext = ROOT.EventFile.iterator.next
except AttributeError : # happens in py3
    orgnext = ROOT.EventFile.iterator.__next__

    

def newnext( it ) :
    obj = orgnext(it)
    #print "Next!", id(obj) # it's reall the same objectproxy each time
    obj.__dict__.clear()
    return obj

ROOT.EventFile.iterator.next = newnext
    

# allow list of strings as argument to translate to vector<string>

def to_vector( lst ) :
    r = ROOT.vector( ROOT.string ) ()
    for item in lst : r.push_back( item )
    return r

# constructors are the __call__ function of the type (/meta-class).
# their first arugment  (args[0]) is allways the type.

xx__oldcall__ = type(ROOT.EventFile).__call__

def new_eventfile_call ( *args ) :

    if len(args) == 2 and type( args[1] ) == list :
        print ( "---> args = ", args )
        v = to_vector( args[1] )
        return xx__oldcall__( args[0], v )

    # fallback to whatever was done before
    return xx__oldcall__ ( *args )

#install the new constructor
type(ROOT.EventFile).__call__ = new_eventfile_call