added ast generator

src/main/java/ASTGenerator.java

@@ -0,0 +1,21 @@
+import abstractSyntaxTree.Class.IClass;
+import abstractSyntaxTree.Class.RefType;
+import abstractSyntaxTree.Node;
+import abstractSyntaxTree.Program;
+import gen.DecafBaseVisitor;
+import gen.DecafParser;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class ASTGenerator extends DecafBaseVisitor<Node> {
+    @Override
+    public Node visitProgram(DecafParser.ProgramContext ctx) {
+        List<RefType> classes = new ArrayList<>();
+        for (DecafParser.ClassdeclContext classDecl : ctx.classdecl()) {
+            Node refType = new RefType(classDecl.Identifier().getText(), new ArrayList<>(), new ArrayList<>());
+            classes.add((RefType) refType);
+        }
+        return new Program(classes);
+    }
+}

src/main/java/Compiler.java

@@ -1,7 +1,6 @@
 import abstractSyntaxTree.Class.FieldDecl;
 import abstractSyntaxTree.Class.MethodDecl;
 import abstractSyntaxTree.Class.RefType;
-import abstractSyntaxTree.Node;
 import abstractSyntaxTree.Program;
 import abstractSyntaxTree.Statement.BlockStatement;
 import gen.DecafLexer;

src/main/java/abstractSyntaxTree/Node.java

@@ -0,0 +1,4 @@
+package abstractSyntaxTree;
+
+public interface Node {
+}

src/main/java/abstractSyntaxTree/Program.java

@@ -3,7 +3,6 @@ package abstractSyntaxTree;
 import TypeCheck.TypeCheckResult;
 import abstractSyntaxTree.Class.FieldDecl;
 import abstractSyntaxTree.Class.MethodDecl;
-import org.objectweb.asm.MethodVisitor;
 import abstractSyntaxTree.Class.RefType;
 import org.objectweb.asm.ClassWriter;
 import org.objectweb.asm.Opcodes;