Utility classes            package:memisc            R Documentation

_N_a_m_e_d _L_i_s_t_s, _L_i_s_t_s _o_f _I_t_e_m_s, _a_n_d _A_t_o_m_i_c _V_e_c_t_o_r_s

_D_e_s_c_r_i_p_t_i_o_n:

     The classes "named.list" and "item.list" are merely some 'helper
     classes' for the construction of the classes "data.set" and
     "importer".

     Class "named.list" extends the basic class "list" by an additional
     slot "names". Its 'initialize' method assures that the names of
     the list are unique.

     Class "item.list" extends the class "named.list", but does not add
     any slots. From "named.list" it differs only by the  'initialize'
     method, which calls that for "named.list" and makes sure that all
     elements of the list belong to  class "item".

     Classes "atomic" and "double" are merely used for method
     selection.

_E_x_a_m_p_l_e_s:

     new("named.list",a=1,b=2)

     # This should generate an error, since the names
     # are not unique.
     try(new("named.list",a=1,a=2))

     # Another error, one name is missing.
     try(new("named.list",a=1,2))

     # Also an error, the resulting list would be unnamed.
     try(new("named.list",1,2))

     new("item.list",a=1,b=2)

     # Also an error: "item.list"s are "named.lists",
     # and here the names would be non-unique.
     try(new("item.list",a=1,a=2))

