[MINOR] Cleanup and print the name of a variable if visited

src/qir/driver/OracleDriver.java

@@ -38,7 +38,6 @@ public final class OracleDriver extends SQLDriver {
     public QIRList run(QIRNode root) {
         QIRSQLVisitor visitor = new QIRSQLVisitor();
         String query = root.accept(visitor);
-        System.out.println("Query: " + query);
         Map<String, String> funs = visitor.popProlog();
         try {
             enableWalnut();

src/qir/driver/PostgreSQLDriver.java

@@ -6,7 +6,6 @@ import java.util.*;
 import qir.ast.*;
 import qir.ast.data.*;
 import qir.driver.ConnectionData;
-import qir.util.QIRPrintVisitor;
 
 /**
  * This driver is the intermediate between QIR and the PostgreSQL database.
@@ -33,15 +32,11 @@ public final class PostgreSQLDriver extends SQLDriver {
     @Override
     public QIRList run(QIRNode root) {
         QIRSQLVisitor visitor = new QIRSQLVisitor();
-        QIRPrintVisitor debugVisitor = new QIRPrintVisitor();
-        System.out.println("Query qir: " + root.accept(debugVisitor));
         String query = root.accept(visitor);
         // TODO: Fix this.
         query = query.startsWith("from ") ? "select * " + query : query;
-        System.out.println("Query: " + query);
         try {
             QIRList result = executeQuery(query);
-            System.out.println("Results qir: " + result.accept(debugVisitor));
             return result;
         } catch (SQLException e) {
             e.printStackTrace();

src/qir/util/IQIRVisitor.java

@@ -31,7 +31,7 @@ public interface IQIRVisitor<T> {
      * @param qirVariable A variable that should have been handled elsewhere.
      */
     public default T visit(QIRVariable qirVariable) {
-        throw new UnsupportedOperationException("Error: we should not visit a QIRVariable.");
+        throw new UnsupportedOperationException("Error: we should not visit a QIRVariable. Tried to visit: " + qirVariable.getId());
     }
 
     public abstract T visit(QIRLambda qirLambda);