Question 2:
==================
15 UNKNOWNs: 3 points each: 45 points.

Consider the following class dictionary SchemaComplex:


import java.util.*;
import java.io.*;
import edu.neu.ccs.demeter.dj.*;
//******************************************************************************
// Basic definitions
//******************************************************************************
Main		= .
List(S)		~ { + *l S -}.
//******************************************************************************
// PART 1:  Definitions of structures implementing the components of the input
// XML schema specification
//******************************************************************************

Schema		= "<" [ <prefixS> NSRef ] "schema"
		    <attrs> List(AttrValue)
		    ">"
		    <items> List(SchemaItem)
		    "</" [ <prefixE> NSRef ] "schema>" *EOF*.
NSRef		= <namespace> Ident ":".
AttrValue	= [ lookahead (@2@) <prefix> NSRef ]
		    <attrName> Ident "=" <attrValue> String.

SchemaItem	: 
		  lookahead (@4@) Annotation |
		  lookahead (@4@) Attribute |
		  lookahead (@4@) ElementItem |
		  lookahead (@4@) TypeDef 
		  | Comment
		  .

Annotation	= "<" [ <prefixS> NSRef ] "annotation>"
		    List(AnnotationContent)
		    "</" [ <prefixE> NSRef ] "annotation>".
AnnotationContent : 
		    lookahead (@4@) Appinfo |
		    lookahead (@4@) Documentation.
Appinfo		= "<" [ <prefixS> NSRef ] "appinfo>"
		    <attrs> List(AttrValue)
		    "</" [ <prefixE> NSRef ] "appinfo>".
Documentation	= "<" [ <prefixS> NSRef ] "documentation"
		    <attrs> List(AttrValue)
		    RestOfDocumentation.
RestOfDocumentation : EmptyDocumentation | NonEmptyDocumentation.
EmptyDocumentation = "/>".
NonEmptyDocumentation = ">"
			  [ <documentation> String ]
			  "</" [ <prefixE> NSRef ] "documentation>".
Attribute	= "<" [ <prefixS> NSRef ] "attribute"
		    <attrs> List(AttrValue)
		    RestOfAttribute.
RestOfAttribute	: EmptyAttribute | NonEmptyAttribute.
EmptyAttribute	= "/>".
NonEmptyAttribute = ">"
		      [ lookahead (@4@) Annotation ]
		      "</" [ <prefixE> NSRef ] "attribute>".

Element		= "<" [ <prefixS> NSRef ] "element"
		    <attrs> List(AttrValue)
		    RestOfElement.
RestOfElement	: EmptyElement | NonEmptyElement.
EmptyElement	= "/>".
NonEmptyElement	= ">"
		    [ lookahead (@4@) Annotation ]
		    [ lookahead (@4@) <type> TypeDef ]
		    "</" [ <prefixE> NSRef ] "element>".

TypeDef		: lookahead (@4@) SimpleType |
		  lookahead (@4@) ComplexType.
SimpleType	= "<" [ <prefixS> NSRef ] "simpleType"
		    <attrs> List(AttrValue)
		    ">"
		    [ lookahead (@4@) Annotation ]
		    "</" [ <prefixE> NSRef ] "simpleType>".

ComplexType	= "<" [ <prefixS> NSRef ] "complexType"
		    <attrs> List(AttrValue)
		    ">"
		    [ lookahead (@4@) Annotation ]
		    ComplexTypeContent
		    List(Attribute)
		    "</" [ <prefixE> NSRef ] "complexType>".
ComplexTypeContent = 
		     [ lookahead (@4@) ElementItem ].

ElementItem	: 
		  lookahead (@4@) Element |
		  lookahead (@4@) SequenceGroup 
		  .

SequenceGroup	= "<" [ <prefixS> NSRef ] "sequence"
		    <attrs> List(AttrValue)
		    ">"
		    [ lookahead (@4@) Annotation ]
		    List(ElementItem)
		    "</" [ <prefixE> NSRef ] "sequence>".

Comment		= "<!--" <comment> String "-->".




Consider the following program that finds
all names of complex types in an XML schema.
The program finds all ComplexType-objects and then searches
the Attribute_List to find an attribute with name "name".

Fr example, the following complex type definition is
introducing a type called PurchaseOrderType.

 <xsd:complexType name="PurchaseOrderType">       

The program will put string "PurchaseOrderType" into a HashSet-object.

Find the UNKNOWNs below.


Schema {
  {{
    HashSet getDefThings(ClassGraph cg){
      String definedThings =
	"from Schema to ComplexType";
      Visitor v = new Visitor(){
	HashSet r = new HashSet();
	void before(ComplexType host){
	  String n = UNKNOWN1.UNKNOWN2().search_name();
	  if (!(n == null)) r.add(n);
        }
	public Object UNKNOWN3(){return r;}
      };
      cg.UNKNOWN4(this,UNKNOWN5,UNKNOWN6);
      return (HashSet) v.UNKNOWN7();
    }
  }}
}

AttrValue_List {
{{
String search_name(){
  UNKNOWN8 en = this.elements();
  String s = new String("name");
  String result;
  while (UNKNOWN9.UNKNOWN10()) {
    UNKNOWN11 n = (UNKNOWN12) en.UNKNOWN13();
    if (s.equals(n.UNKNOWN14().toString())) {
      result = n.UNKNOWN15();
      System.out.println("Type " + result + " found");
      return result;
    }
  }
  System.out.println("NOTHING FOUND");
  return null;
}
}}
}

If getDefThings(..) is called on the Schema-object
described in XML2AP.input:

<xsd:schema xmlns:xsd="http://www.w3.org/2000/08/XMLSchema">

 <xsd:annotation>
  < xsd : documentation >
   "Purchase order schema for Example.com.  Copyright 2000 Example.com. All rights reserved."
  </xsd:documentation>
 </xsd:annotation>

 <xsd:element name="purchaseOrder" type="PurchaseOrderType"/>

 <xsd:element name="comment" type="xsd:string"/>

 <xsd:complexType name="PurchaseOrderType">
  < xsd : sequence >
   <xsd:element name="shipTo" type="USAddress"/>
   <xsd:element name="billTo" type="USAddress"/>
   <xsd:element ref="comment" minOccurs="0"/>
   <xsd:element name="items"  type="Items"/>
  </xsd:sequence>
  <xsd:attribute name="orderDate" type="xsd:date"/>
 </xsd:complexType>

 <xsd:complexType name="USAddress">
  < xsd : sequence >
   <xsd:element name="name"   type="xsd:string"/>
   <xsd:element name="street" type="xsd:string"/>
   <xsd:element name="city"   type="xsd:string"/>
   <xsd:element name="state"  type="xsd:string"/>
   <xsd:element name="zip"    type="xsd:decimal"/>
  </xsd:sequence>
  <xsd:attribute name="country" type="xsd:NMTOKEN"
     use="fixed" value="US"/>
 </xsd:complexType>

 <xsd:complexType name="Items">
  <xsd:sequence >
   <xsd:element name="item" minOccurs="2" maxOccurs="unbounded">
    <xsd:complexType >
     <xsd:sequence >
      <xsd:element name="productName" type="xsd:string" maxOccurs="unbounded"/>
      <xsd:element name="quantity" type="xsd:positiveInteger"/>
      <xsd:element name="USPrice"  type="xsd:decimal"/>
      <xsd:element ref="comment"   minOccurs="0" maxOccurs="unbounded"/>
      <xsd:element name="shipDate" type="xsd:date" minOccurs="0"/>
     </xsd:sequence>
     <xsd:attribute name="partNum" type="string"/>
    </xsd:complexType>
   </xsd:element>
  </xsd:sequence>
 </xsd:complexType>

</xsd:schema>


we get the following output:

Type PurchaseOrderType found
Type USAddress found
Type Items found
NOTHING FOUND