Index: src/libcfa/iostream
===================================================================
--- src/libcfa/iostream	(revision 53a6c2a24c63e4878fd4222e11fef110ba3ee85a)
+++ src/libcfa/iostream	(revision 74b007ba1f2facc85656ade19a8bab1d56bb0a82)
@@ -10,6 +10,6 @@
 // Created On       : Wed May 27 17:56:53 2015
 // Last Modified By : Peter A. Buhr
-// Last Modified On : Fri Jul  7 08:35:59 2017
-// Update Count     : 118
+// Last Modified On : Wed Aug  9 16:42:47 2017
+// Update Count     : 131
 //
 
@@ -46,6 +46,10 @@
 }; // ostream
 
-trait writeable( otype T ) {
-	forall( dtype ostype | ostream( ostype ) ) ostype * ?|?( ostype *, T );
+// trait writeable( otype T ) {
+// 	forall( dtype ostype | ostream( ostype ) ) ostype * ?|?( ostype *, T );
+// }; // writeable
+
+trait writeable( otype T, dtype ostype | ostream( ostype ) ) {
+	ostype * ?|?( ostype *, T );
 }; // writeable
 
@@ -77,5 +81,6 @@
 
 // tuples
-forall( dtype ostype, otype T, ttype Params | ostream( ostype ) | writeable( T ) | { ostype * ?|?( ostype *, Params ); } ) ostype * ?|?( ostype * os, T arg, Params rest );
+forall( dtype ostype, otype T, ttype Params | writeable( T, ostype ) | { ostype * ?|?( ostype *, Params ); } )
+ostype * ?|?( ostype * os, T arg, Params rest );
 
 // manipulators
@@ -90,9 +95,9 @@
 
 // writes the range [begin, end) to the given stream
-forall( otype elt_type | writeable( elt_type ), otype iterator_type | iterator( iterator_type, elt_type ), dtype os_type | ostream( os_type ) )
-void write( iterator_type begin, iterator_type end, os_type *os );
+forall( dtype ostype, otype elt_type | writeable( elt_type, ostype ), otype iterator_type | iterator( iterator_type, elt_type ) )
+void write( iterator_type begin, iterator_type end, ostype * os );
 
-forall( otype elt_type | writeable( elt_type ), otype iterator_type | iterator( iterator_type, elt_type ), dtype os_type | ostream( os_type ) )
-void write_reverse( iterator_type begin, iterator_type end, os_type *os );
+forall( dtype ostype, otype elt_type | writeable( elt_type, ostype ), otype iterator_type | iterator( iterator_type, elt_type ) )
+void write_reverse( iterator_type begin, iterator_type end, ostype * os );
 
 //---------------------------------------