The source of this document is at:

http://www.ccs.neu.edu/research/demeter/sources/DemeterJava/examples/j-check-TBR1/evolution-steps

Info about Java source code:
http://www.ccs.neu.edu/research/demeter/sources/DemeterJava/examples/j-check-TBR1/README

The three programs in
../j-check-TBR1
../j-check-TBR2
../j-check-TBR3

Presents an evolution of the Terminal-Buffer-Rule checker
(page 393 of AP book)
over three increasingly larger class dictionaries.
See also:
http://www.ccs.neu.edu/research/demeter/course/f96/hw/3/assign.html
For the first two class dictionaries, the adaptive programs are identical.
For the third one, the adaptive program needed to be adjusted.
Both the traversal specifications and the Java programs.

The three programs serve as an example of how adaptive programs
should be developed. Initially a barebone class dictionary is used
to get the program going. The class dictionary is gradually enlarged
to add more behavior.

An evolutionary mechanism is needed so that only the first program needs 
to be updated and then the third can be created automatically
for many evolutions of the first program.
Evolution history linking would be a good name for such a mechanism.
The advantages would be that multiple variants of the the same program
could be maintained more easily.

CLASS DICTIONARY 1: program.cd in j-check-TBR1
---------------------------------------------

(@
	import java.util.Vector;
@)

// class dictionary
Cd_graph = <first> Adj.
Adj = <vertex> Vertex <ns> Construct ".".
Construct = "=" <l1> Labeled_vertex <l2> Labeled_vertex.
Labeled_vertex = "<" <label_name> Ident ">" 
                     <class_name> Vertex.
Vertex = <name> Ident.


// Visitors

Main = .

IsDemeterClassVisitor = 
  // vector of cd defined class names 
  <cd_defined_classes_out> ClassNames. 
CheckingVisitor = 
  // vector of cd defined class names 
  <cd_defined_classes_in> ClassNames
  <className> Vertex // current class
  <p> Integer // number of parts per class
  <pt> Integer // number of terminal parts per class
  <passed> Boolean
  .
ClassNames = *extends* Vector. // Vector(Ident)

BEHAVIOR FILE: program.beh in j-check-TBR1
------------------------------------------------
Cd_graph {
// find Demeter classes: results in vector of class names
	traversal allClassDefinitions( IsDemeterClassVisitor dcv ) {
		bypassing{ -> *,ns,* } to Vertex;
	}
  (@
  ClassNames findDemClasses(){
    IsDemeterClassVisitor dcv = new IsDemeterClassVisitor(new ClassNames());
    this.allClassDefinitions( dcv );
    ClassNames cns = dcv.get_cd_defined_classes_out();
    System.out.println(" first and last class " + 
    cns.firstElement() + " " + cns.lastElement() + " size of vector " + 
    cns.size());
    return dcv.get_cd_defined_classes_out();
  }
  @)

// count number of parts (p) init per class def.
// count number of parts whose class is terminal (pt) init per class def.
// at end of construction class: if pt > 0 and p > 1 then violation.
	traversal allClasses ( CheckingVisitor ckv ) {
		bypassing {Alternat} to Vertex;
	}
  (@
  boolean checkTBR(ClassNames demClasses) {
    CheckingVisitor ckv = new CheckingVisitor();
    // transfer information
    ckv.set_cd_defined_classes_in(demClasses);
    ckv.set_passed(new Boolean(true));
    this.allClasses( ckv );
    return ckv.get_passed().booleanValue();
  }
  @)
}
CheckingVisitor {
  (@
  void inc_p() { set_p(new Integer(get_p().intValue() + 1)); }
  void inc_pt() { set_pt(new Integer(get_pt().intValue() + 1)); }
  void init_p() { set_p(new Integer(0)); }
  void init_pt() { set_pt(new Integer(0)); }
  @)

	before -> Adj, vertex, Vertex (@
		this.set_className( new Vertex( dest.get_name() ) );
		init_p();
		init_pt();
	@)

	before  -> Labeled_vertex, *, Vertex 
	(@
		inc_p();
		System.out.println(" target class " 
		  + dest.get_name().toString());
//		if ( this.get_cd_defined_classes_in().contains(
//		  dest.get_name())) {System.out.println ("CONTAINED");}
//       		else { inc_pt();}

		if ( this.get_cd_defined_classes_in().
		       indexOf( dest.get_name() ) == -1 ) {
			 inc_pt();}
	@)
	
	after Construct (@
        int pti = pt.intValue();
        int pi = p.intValue();
	System.out.println(" parts " + pi + " terminal parts " + pti);
	if (( pti > 0 ) & (pi > 1))
	{ set_passed(new Boolean(false));
	  System.out.print( "Class violates the" +
		" Terminal Buffer Rule: " );
		System.out.println(className.get_name() );
		}
	@)

}

Main {
(@
	static public void main (String args[]) throws Exception
	{
		Cd_graph example = Cd_graph.parse( System.in );
if (example.checkTBR(example.findDemClasses()))
		{ System.out.println( "Passed!" ); }
	}
@)
}

// for big cd
//  traversal IsDemeterClassTraversal(IsDemeterClassVisitor v) {
//     bypassing { ClassParts, ClassMethods, -> *, parameters, * } to ClassName;

IsDemeterClassVisitor {
   before Vertex (@
         this.get_cd_defined_classes_out().
	   addElement(host.get_name());
   @)
}

}

INPUT 1: program.input in j-check-TBR1
-----------------------------------------
A = <x> A <i> A.

OUTPUT:
java Main < program.input
 first and last class A A size of vector 1
 target class A
 target class A
 parts 2 terminal parts 0
Passed!

CLASS DICTIONARY 2: program.cd in j-check-TBR2
---------------------------------------------
(@
	import java.util.Vector;
@)

// class dictionary
Cd_graph = <first> Adj <rest> Adj_list.
Adj = <vertex> Vertex <ns> Neighbors ".".
Neighbors: Construct | Alternat.
Construct = "=" <c_ns> Any_vertex_list.
Alternat = ":" <first> Vertex "|" <second> Vertex.
Any_vertex : Labeled_vertex | Syntax_vertex.
Syntax_vertex = <string> String.
Labeled_vertex = "<" <label_name> Ident ">" 
                     <class_name> Vertex.
Adj_list: Cd_graph | Empty_cd_graph .
Any_vertex_list: Nany_vertex_list | Empty.
Nany_vertex_list = 
  <first> Any_vertex <rest> Any_vertex_list.
Empty = .
Empty_cd_graph = .
Vertex = <name> Ident.


// Visitors

Main = .

IsDemeterClassVisitor = 
  // vector of cd defined class names 
  <cd_defined_classes_out> ClassNames. 
CheckingVisitor = 
  // vector of cd defined class names 
  <cd_defined_classes_in> ClassNames
  <className> Vertex // current class
  <p> Integer // number of parts per class
  <pt> Integer // number of terminal parts per class
  <passed> Boolean
  .
ClassNames = *extends* Vector. // Vector(Ident)

INPUT 2: program.input in j-check-TBR2
-----------------------------------------
A1 = <b> A1 <c> A1.
A2 = <b> A1 <c> A1.
A = "x" <x> X <i> Integer.
X = .
B = <l> Long.
C = <i1> Integer <i2> Integer.
T : R | S.
S = <v> Vector <a> A.