extremely minimal AST layer

ql/src/codeql_ql/ast/Ast.qll

@@ -0,0 +1,24 @@
+import ql
+private import codeql_ql.ast.internal.AstNodes
+
+/** An AST node of a QL program */
+class AstNode extends TAstNode {
+  string toString() { result = "ASTNode" }
+
+  Location getLocation() { result = toGenerated(this).getLocation() }
+}
+
+/**
+ * A classless predicate.
+ */
+class ClasslessPredicate extends TClasslessPredicate, AstNode {
+  Generated::ModuleMember member;
+  Generated::ClasslessPredicate pred;
+
+  ClasslessPredicate() { this = TClasslessPredicate(member, pred) }
+
+  predicate isPrivate() {
+    member.getAFieldOrChild().(Generated::Annotation).getName().getValue() = "private"
+  }
+}
+

ql/src/codeql_ql/ast/internal/AstNodes.qll

@@ -0,0 +1,13 @@
+import codeql_ql.ast.Ast as AST
+import TreeSitter
+
+cached
+newtype TAstNode =
+  TClasslessPredicate(Generated::ModuleMember member, Generated::ClasslessPredicate pred) {
+    pred.getParent() = member
+  }
+
+/**
+ * Gets the underlying TreeSitter entity for a given AST node.
+ */
+Generated::AstNode toGenerated(AST::AstNode n) { n = TClasslessPredicate(_, result) }

ql/src/ql.qll

@@ -1,3 +1,3 @@
 import codeql.Locations
 import codeql.files.FileSystem
-import codeql_ql.ast.internal.TreeSitter::Generated
+import codeql_ql.ast.Ast