MIDTERM               COM 1205                   Winter 2003
Tuesday, February 11				 Karl Lieberherr

Open book and open notes.

Question 1: 71
Question 2: 20
Question 3. 40
  131 points

Question 1:
===========
28 UNKNOWNs:
24 - 28: 5 points each: 25
1  - 23: 2 points each: 46
			--
			71

Consider the following program.cd, program.beh and program.input
file and the output. Find the UNKNOWNS.


program.cd:
===============================================================

import edu.neu.ccs.demeter.dj.*;

Main = <s> String.

Aspect = "aspect" 
  <an> TraversalAspectName 
  <sts> SList(Decl). 
Decl = "declare" Item.
Item : NamedStrat | Trav.
NamedStrat = "strategy" ":" StrategyName ":" Strat.
Trav = "traversal" ":" 
  MethodSignature ":" StrategyName "(" ClassName ")".
MethodSignature = "void" MethodName "(" FormalArgument ")".
FormalArgument = ClassName VariableName.

TraversalAspectName = Ident.
StrategyName = Ident.
ClassName = Ident.
MethodName = Ident.
Strat = String.
VariableName = Ident.

SList(S) ~ "{" S {";" S } "}".

program.beh:
===============================================================

Main {
  {{
  static ClassGraph cg;
  public static void main(String args[]) throws Exception {
    Aspect m = Aspect.parse(System.in);
    System.out.println("input ===================== ");
    m.display();
    System.out.println();
    System.out.println(" processing starts ");
    cg = new ClassGraph(true, false);
    cg.traverse(m,
      "from Aspect to ClassName", new Visitor() {
    void before (ClassName host) {
      System.out.println(host.get_ident().toString());
    }
    });
    System.out.println("done: from Aspect to ClassName");

    cg.traverse(m,
      "from Aspect via MethodSignature to ClassName", new Visitor() {
    void before (ClassName host) {
      System.out.println(host.get_ident().toString());
    }
    });
    System.out.println("done: from Aspect via MethodSignature to ClassName");
  }
  }}
}

program.input:
===============================================================

aspect Traversals {
  declare strategy: eachCommand: "from Commands to Command";
  declare traversal:
    void interpret(CompoundFile cd): eachCommand(Interpreter)
}

OUTPUT:
==============================================================


input ===================== 
: Aspect  (
  <an> : UNKNOWN1  (
    <ident>  : UNKNOWN2 "UNKNOWN3" )
  <sts> : Decl_SList  {
    <first> : Nonempty_Decl_SList  (
      <it> : UNKNOWN4  (
        <UNKNOWN5> : UNKNOWN6  (
	  <UNKNOWN7> : UNKNOWN8  (
		<ident>  : Ident "UNKNOWN9" )
	  <strat> : Strat  (
		<string>  : String UNKNOWN10  ) ) )
     <next> : Nonempty_Decl_SList  (
      <it> : Decl  (
	<item> : Trav  (
		<methodsignature> : MethodSignature  (
			<methodname> : MethodName  (
				<ident>  : Ident "UNKNOWN11" )
			<formalargument> : FormalArgument  (
				<classname> : ClassName  (
					<ident>  : Ident "UNKNOWN12" )
				<variablename> : VariableName  (
					<ident>  : Ident "UNKNOWN13" ) ) )
		<UNKNOWN14> : UNKNOWN15  (
			<UNKNOWN16>  : UNKNOWN17 "UNKNOWN18" )
		<UNKNOWN19> : UNKNOWN20  (
			<UNKNOWN21>  : UNKNOWN22 "UNKNOWN23" ) ) ) ) ) } )
 processing starts 
UNKNOWN24
UNKNOWN25
UNKNOWN26
UNKNOWN27
UNKNOWN28


Question 2:
=========================================================================
20 points

The following lines from the above *.beh file
contain significant duplication.
Rewrite the program so that the duplication is minimized
and the behavior stays the same.

cg.traverse(m,
  "from Aspect to ClassName", new Visitor() {
    void before (ClassName host) {
      System.out.println(host.get_ident().toString());
    }
    });

cg.traverse(m,
  "from Aspect via MethodSignature to ClassName", new Visitor() {
    void before (ClassName host) {
      System.out.println(host.get_ident().toString());
    }
    });

Put your result into UNKNOWN1.

Question 3:
==========================================================================
40 points


Is the following a legal sentence with respect to the
above class dictionary in question 1? Explain.


aspect Traversals {
  declare strategy: eachCommand: "from Commands to Command";
   declare traversal:
       void listAll(): eachFile(FileLister);
   declare traversal:
       void listAll(X x, Y y): eachFile(FileLister);
}

If it is illegal describe how you would change the
class dictionary.

Only give the modified and new classes.

Put your result into UNKNOWN1.