diff --git a/src/preprocessor/index.ts b/src/preprocessor/index.ts
index 4c1a89c..f416c42 100644
--- a/src/preprocessor/index.ts
+++ b/src/preprocessor/index.ts
@@ -3,6 +3,7 @@ import {
   preprocessAst,
   preprocessComments,
   PreprocessorOptions,
+  visitPreprocessedAst,
 } from './preprocessor.js';
 
 // This index file is currently only for package publishing, where the whole
@@ -20,4 +21,4 @@ const preprocess = (src: string, options: PreprocessorOptions) =>
 
 export default preprocess;
 
-export { preprocessAst, preprocessComments, generate, preprocess, parser };
+export { preprocessAst, preprocessComments, generate, preprocess, parser, visitPreprocessedAst };
diff --git a/src/preprocessor/preprocessor-grammar.pegjs b/src/preprocessor/preprocessor-grammar.pegjs
index 326d601..fca70f3 100644
--- a/src/preprocessor/preprocessor-grammar.pegjs
+++ b/src/preprocessor/preprocessor-grammar.pegjs
@@ -77,6 +77,7 @@ UNDEF = wsStart:_? token:"#undef" wsEnd:_? { return node('literal', { literal: t
 ERROR = wsStart:_? token:"#error" wsEnd:_? { return node('literal', { literal: token, wsStart, wsEnd }); }
 PRAGMA = wsStart:_? token:"#pragma" wsEnd:_? { return node('literal', { literal: token, wsStart, wsEnd }); }
 DEFINED = wsStart:_? token:"defined" wsEnd:_? { return node('literal', { literal: token, wsStart, wsEnd }); }
+DEFINED_WITH_END_WS = wsStart:_? token:"defined" wsEnd:__ { return node('literal', { literal: token, wsStart, wsEnd }); }
 IF = wsStart:_? token:"#if" wsEnd:_? { return node('literal', { literal: token, wsStart, wsEnd }); }
 IFDEF = wsStart:_? token:"#ifdef" wsEnd:_? { return node('literal', { literal: token, wsStart, wsEnd }); }
 IFNDEF = wsStart:_? token:"#ifndef" wsEnd:_? { return node('literal', { literal: token, wsStart, wsEnd }); }
@@ -224,6 +225,9 @@ unary_expression "unary expression"
   = operator:DEFINED lp:LEFT_PAREN identifier:IDENTIFIER rp:RIGHT_PAREN {
     return node('unary_defined', { operator, lp, identifier, rp, });
   }
+  / operator:DEFINED_WITH_END_WS identifier:IDENTIFIER {
+    return node('unary_defined', { operator, identifier});
+  }
   / operator:(PLUS / DASH / BANG / TILDE)
     expression:unary_expression {
       return node('unary', { operator, expression });
@@ -323,10 +327,18 @@ logical_or_expression "logical or expression"
 // I added this as a maybe entry point to expressions
 constant_expression "constant expression" = logical_or_expression
 
+// Must have a space or a comment
+__ "whitespace or comment" = w:whitespace rest:(comment whitespace?)* {
+  return collapse(w, rest);
+}
+/ c:comment rest:(whitespace comment?)* {
+  return collapse(c, rest);
+}
+
 // The whitespace is optional so that we can put comments immediately after
 // terminals, like void/* comment */
 // The ending whitespace is so that linebreaks can happen after comments
-_ "whitespace or comment" = w:whitespace? rest:(comment whitespace?)* {
+_ "whitespace or comment or null" = w:whitespace? rest:(comment whitespace?)* {
   return collapse(w, rest);
 }
 
diff --git a/src/preprocessor/preprocessor.test.ts b/src/preprocessor/preprocessor.test.ts
index d9be523..910f98c 100644
--- a/src/preprocessor/preprocessor.test.ts
+++ b/src/preprocessor/preprocessor.test.ts
@@ -477,6 +477,25 @@ test('generate #ifdef & #ifndef & #else', () => {
 `);
 });
 
+
+test('parse defined && defined() && definedXXX', () => {
+  const program = `
+#if defined AAA && defined/**/BBB && defined/**/ CCC && definedXXX && defined(DDD)
+#endif
+`;
+  const ast = parse(program);
+  const astStr = JSON.stringify(ast);
+  expect(astStr.includes('"identifier":"definedXXX"')).toBeTruthy();
+  expect(astStr.includes('"identifier":"AAA"')).toBeTruthy();
+  expect(astStr.includes('"identifier":"BBB"')).toBeTruthy();
+  expect(astStr.includes('"identifier":"CCC"')).toBeTruthy();
+  expect(astStr.includes('"identifier":"DDD"')).toBeTruthy();
+  expect(astStr.includes('"identifier":"XXX"')).toBeFalsy();
+  expect(astStr.match(/unary_defined/g)?.length).toBe(4);
+
+  expectParsedProgram(program);
+});
+
 /*
 test('debug', () => {
   const program = `
diff --git a/src/preprocessor/preprocessor.ts b/src/preprocessor/preprocessor.ts
index a07ed47..04e8b14 100644
--- a/src/preprocessor/preprocessor.ts
+++ b/src/preprocessor/preprocessor.ts
@@ -434,7 +434,7 @@ type VisitorOverride = (
 ) => void;
 
 // @ts-ignore
-const visitPreprocessedAst = visit as VisitorOverride;
+export const visitPreprocessedAst = visit as VisitorOverride;
 
 type PathOverride<NodeType> = {
   node: NodeType;