G_DISPLAYASTREE(2)      Demeter Software       G_DISPLAYASTREE(2)



NAME
     g_displayAsTree - displays a tree  object  in  object  graph
     notation.


SYNOPSIS
     void _g__d_i_s_p_l_a_y_A_s_T_r_e_e ( ostream& strm = cout )


DESCRIPTION
     _g__d_i_s_p_l_a_y_A_s_T_r_e_e displays a detailed description of an object
     using the object graph notation. If the _s_t_r_m
      argument is provided,  then  the  output  is  sent  to  the
     ostream  in  the given .I strm, otherwise the output is sent
     to the standard output. The object must be  a  tree  object.
     That is, it cannot have any cycles or shared subobjects. The
     class of the object is displayed preceded by  a  colon,  and
     followed by an open delimiter, the description of the compo-
     sition of the object, and a close delimiter. If the class of
     the object is a construction class the open and close delim-
     iters are "(" and ")", respectively, and the composition  of
     the  object is a number of part objects. If the class of the
     object is a repetition class the open and  close  delimiters
     are  "{"  and  "}", respectively, and the composition of the
     object is a sequence of repeated element objects. Each  part
     object  or  repeated  element object is in turn displayed in
     object graph format in a similar fashion. Each  part  object
     is  preceded  by  a label indicating the name of the part in
     the class dictionary that defines the object  that  contains
     the  part.  If  the  class of the object is a terminal class
     (i.e., Ident, Number, Real, String, or Text), then no delim-
     iters  are  displayed  and  the composition of the object is
     simply a quoted value.


EXAMPLE
     Here is an example of how to use _g__d_i_s_p_l_a_y_A_s_T_r_e_e.

     Assume the following class dictionary.

     Example = <ex> List(Prefix).
     Prefix : Simple | Compound.
     Simple = <val> Number.
     Compound = "(" <op> Op <args> List(Prefix) ")".
     Op : AddSym | MulSym.
     AddSym = "+".
     MulSym = "*".
     List(S) ~ S { S }.

     The following  program  parses  in  a  Compound  object  and
     displays it as a tree object.




Demeter           Last change: 27 February 1992                 1






G_DISPLAYASTREE(2)      Demeter Software       G_DISPLAYASTREE(2)



     Compound* iCompound = new Compound();
     iCompound = (Compound*)iCompound->g_parse("demeter-input");

     ostream outFile( "compound-object-graph" );
     iCompound->g_displayAsTree( outFile );

     If the contents of demeter-input is (* (+ 3 4) 3), then  the
     following text is written to the file compound-object-graph.
     An example of an object graph is as follows:

     : Compound (
        < op > : MulSym ( )
        < args > : Prefix_List {
           : Compound (
              < op > : AddSym ( )
              < args > : Prefix_List {
                 : Simple (
                    < val > : Number "3" ) ,
                 : Simple (
                    < val > : Number "4" ) } ) ,
           : Simple (
              < val > : Number "3" ) } )

     If no argument had been given, then the description is  sent
     to the standard output.


SEE ALSO
     g_parse(2)


REFERENCES
     _U_s_e_r _M_a_n_u_a_l _f_o_r _T_h_e _C++ _D_e_m_e_t_e_r
     Walter L. Hursch
     Northeastern University, 1993


           _T_h_e _A_n_n_o_t_a_t_e_d _C++ _R_e_f_e_r_e_n_c_e _M_a_n_u_a_l
     Margaret A. Ellis and Bjarne Stroustrup
     Addison-Wesley, 1990

     _C++ _P_r_i_m_e_r
     Stanley B. Lippman
     Addison-Wesley, 1989











Demeter           Last change: 27 February 1992                 2