((function sign
   (signature int
     (parameters
       (declare (in) int x))
     ((return (expression int sign (var_ref x)))))

   (signature ivec2
     (parameters
       (declare (in) ivec2 x))
     ((return (expression ivec2 sign (var_ref x)))))

   (signature ivec3
     (parameters
       (declare (in) ivec3 x))
     ((return (expression ivec3 sign (var_ref x)))))

   (signature ivec4
     (parameters
       (declare (in) ivec4 x))
     ((return (expression ivec4 sign (var_ref x)))))
))