.TH G_DISPLAYASTREE 2 "27 February 1992" "Demeter" "Demeter Software"

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

.SH SYNOPSIS

void 
.I g_displayAsTree
( ostream& strm = cout )

.SH DESCRIPTION

.I g_displayAsTree
displays a detailed description of an object using the object graph
notation. If the 
.I strm
 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 composition of the object, and a close delimiter. If
the class of the object is a construction class the open and close
delimiters 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 delimiters are displayed and the composition of the
object is simply a quoted value.

.SH EXAMPLE
Here is an example of how to use
.I g_displayAsTree.

Assume the following class dictionary.

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

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

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

ostream outFile( "compound-object-graph" );
.br
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 (
.br
   < op > : MulSym ( )
.br
   < args > : Prefix_List {
.br
      : Compound (
.br
         < op > : AddSym ( )
.br
         < args > : Prefix_List {
.br
            : Simple (
.br
               < val > : Number "3" ) ,
.br
            : Simple (
.br
               < val > : Number "4" ) } ) ,
.br
      : Simple (
.br
         < val > : Number "3" ) } )

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

.SH SEE ALSO
g_parse(2)

.SH REFERENCES 

.I User Manual for The C++ Demeter System
.br
Walter L. Hursch
.br
Northeastern University, 1993


	
.I The Annotated C++ Reference Manual
.br
Margaret A. Ellis and Bjarne Stroustrup
.br
Addison-Wesley, 1990

.I C++ Primer
.br
Stanley B. Lippman
.br
Addison-Wesley, 1989