=== modified file 'escape.pl'
--- escape.pl	2011-11-26 19:12:18 +0000
+++ escape.pl	2011-11-26 17:51:17 +0000
@@ -45,7 +45,6 @@
                             r_strip(AString, "/", AStripped),
                             l_strip(BString, "/", BStripped),
                             concat([AStripped, "/", BStripped, End], Joined)
-    ;                       throw(unable_to_convert_to_string(X))
     ).
 
 str(X, S) :- str_dlist(X, S, []).

=== modified file 'stagebuilder.pl'
--- stagebuilder.pl	2011-11-26 19:12:18 +0000
+++ stagebuilder.pl	2011-11-26 17:51:17 +0000
@@ -101,7 +101,7 @@
 %     maplist(print_solution, Solutions).
 
 cmd_repr(Command) :-
-    write('representation of: '), writeq(Command), write(' ::'), nl,
+    write('representation of: '), portray_clause(Command), write(' ::'), nl,
     (  setof(Lines , maplist(format_cmd, [Command], Lines), Solutions)
     -> maplist(print_solution, Solutions)
     ;  write('FAILED!'), nl, trace, format_cmd(Command, _)
@@ -223,8 +223,8 @@
 gentoo_package(base_x11, [
         package_world('ccx-meta/base-x11')
     ], [
-        '256-color', 'X', apng, cairo, exif, gif, gstreamer, gtk, imlib, jpeg,
-        opengl, png, sdl, 'sdl-image', tcl, tk, tiff, truetype, webkit, xcb, xpm
+        256-color, 'X', apng, cairo, exif, gif, gstreamer, gtk, imlib, jpeg,
+        opengl, png, sdl, sdl-image, tcl, tk, tiff, truetype, webkit, xcb, xpm
     ]).
 gentoo_package(filesystem_utilities, [
         package_world('ccx-meta/filesystem-utilities')
@@ -269,16 +269,8 @@
 
 % USE handling
 
-use_check_atom(Use) :-
-    (  atom(Use)
-    -> true
-    ;  throw(use_is_not_simple_atom(Use))
-    ).
-
 gentoo_package_use(Name, UseEnabledSet, UseDisabledSet) :-
     gentoo_package(Name,_Echos, UseEnabledList, UseDisabledList),
-    maplist(use_check_atom, UseEnabledList),
-    maplist(use_check_atom, UseDisabledList),
     list_to_ord_set(UseEnabledList, UseEnabledSet),
     list_to_ord_set(UseDisabledList, UseDisabledSet).