.TH G_DRAW 2 "24 September 1991" "Demeter" "Demeter Software"

.SH NAME
g_draw \- sends the generic draw message to an object.

.SH SYNOPSIS

virtual void Universal::
.I g_draw()

.SH DESCRIPTION

.I g_draw
displays a detailed description of an object using an indented tree
format. The class of the object is displayed, followed by a descriptor
that depends on the type of class the object belongs to. If the class of
the object is a construction class, the descriptor HAS n PARTS is
displayed, where n is the number of parts as defined in the class
dictionary. If the class of the object is a repetition class, the
descriptor HAS n ELEMENTS is displayed, where n is the number of actual
repeated elements in the object. In either case, the composition of the
object is displayed by sending the
.I g_draw
message to each part or element of the object. If the object is of a
terminal class (i.e., Ident, Number, Real, String, or Text), then instead of
describing the composition of the object, the value of the object is
displayed. If the class of the object is a construction class and one of
its optional components is not present, then
.I g_draw
displays the message "Missing optional part!" instead of sending the
.I g_draw
message to the nonexistent object. The receiving object must be a tree
object. That is, it cannot have any cycles or shared subobjects.

.SH REDEFINITION
Since
.I g_draw
is a virtual function, it can be redefined at any user class. This
means that the user can change the way in which
.I g_draw
displays a particular class of objects. As a technical consideration,
making
.I g_draw
virtual allows to define it recursively and to give the termination
condition as a redefinition at the terminal classes DemIdent, DemNumber,
DemReal, DemString, and DemText.

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

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

.br
iCompound->g_draw();

.SH SEE ALSO
g_parse(2), terminal(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