diff --git a/racket/syndicate/syntax-classes.rkt b/racket/syndicate/syntax-classes.rkt
new file mode 100644
index 0000000..1504a46
--- /dev/null
+++ b/racket/syndicate/syntax-classes.rkt
@@ -0,0 +1,21 @@
+#lang racket/base
+;; Common syntax classes.
+
+(provide (for-syntax assertions
+                     name))
+
+(require (for-syntax racket/base))
+(require (for-syntax syntax/parse))
+(require (for-syntax syntax/srcloc))
+
+(require "trie.rkt")
+
+(begin-for-syntax
+  (define-splicing-syntax-class assertions
+    (pattern (~seq #:assertions P0) #:attr P #'(pattern->trie '<initial-assertions> P0))
+    (pattern (~seq #:assertions* P)) ;; P should be an expression yielding a trie
+    (pattern (~seq) #:attr P #'trie-empty))
+
+  (define-splicing-syntax-class name
+    (pattern (~seq #:name N))
+    (pattern (~seq) #:attr N #'#f)))