wenzelm [Tue, 22 Mar 2011 13:32:20 +0100] rev 42048
support for encoded positions (for id_position, longid_position) as pseudo type-constraints -- still inactive;
simplified/generalized abs_tr/binder_tr: allow iterated constraints, stemming from positions;
Ast.pretty_ast: special treatment of encoded positions;
eliminated Ast.str_of_ast in favour of uniform Ast.pretty_ast;