SClassExtension-class        package:methods        R Documentation

_C_l_a_s_s _t_o _R_e_p_r_e_s_e_n_t _I_n_h_e_r_i_t_a_n_c_e (_E_x_t_e_n_s_i_o_n) _R_e_l_a_t_i_o_n_s

_D_e_s_c_r_i_p_t_i_o_n:

     An object from this class represents a single 'is' relationship;
     lists of these objects are used to represent all the extensions
     (superclasses) and subclasses for a given class.  The object
     contains information about how the relation is defined and methods
     to coerce, test, and replace correspondingly.

_O_b_j_e_c_t_s _f_r_o_m _t_h_e _C_l_a_s_s:

     Objects from this class are generated by 'setIs', from direct
     calls and from the 'contains=' information in a call to
     'setClass', and from class unions created by 'setClassUnion'. In
     the last case, the information is stored in defining the
     _subclasses_ of the union class (allowing unions to contain sealed
     classes).

_S_l_o_t_s:


     '_s_u_b_C_l_a_s_s,_s_u_p_e_r_C_l_a_s_s': The classes being extended: corresponding
          to the 'from', and 'to' arguments to 'setIs'. 

     '_p_a_c_k_a_g_e': The package to which that class belongs. 

     '_c_o_e_r_c_e': A function to carry out the as() computation implied by
          the relation.  Note that these functions should _not_ be used
          directly.  They only deal with the 'strict=TRUE' calls to the
          'as' function, with the full method constructed from this
          mechanically. 

     '_t_e_s_t': The function that would test whether the relation holds. 
          Except for explicitly specified 'test' arguments to 'setIs',
          this function is trivial. 

     '_r_e_p_l_a_c_e': The method used to implement 'as(x, Class) <- value'.

     '_s_i_m_p_l_e': A '"logical"' flag, 'TRUE' if this is a simple relation,
          either because one class is contained in the definition of
          another, or because a class has been explicitly stated to
          extend a virtual class.  For simple extensions, the three
          methods are generated automatically.

     '_b_y': If this relation has been constructed transitively, the
          first intermediate class from the subclass. 

     '_d_a_t_a_P_a_r_t': A '"logical"' flag, 'TRUE' if the extended class is in
          fact the data part of the subclass.  In this case the
          extended class is a basic class (i.e., a type). 

     '_d_i_s_t_a_n_c_e': The distance between the two classes, 1 for directly
          contained classes, plus the number of generations between
          otherwise.   

_M_e_t_h_o_d_s:

     No methods defined with class '"SClassExtension"' in the
     signature.

_S_e_e _A_l_s_o:

     'is', 'as', and the 'classRepresentation' class.

