diff --git a/module/mes/scm.mes b/module/mes/scm.mes
index 9beac54b..9bd53581 100644
--- a/module/mes/scm.mes
+++ b/module/mes/scm.mes
@@ -351,3 +351,7 @@
 (define (negate proc)
   (lambda args
     (not (apply proc args))))
+
+(define (const . rest)
+  (lambda (. _)
+    (car rest)))
diff --git a/tests/scm.test b/tests/scm.test
index 7254d184..98055a9f 100755
--- a/tests/scm.test
+++ b/tests/scm.test
@@ -159,4 +159,7 @@ exit $?
 (pass-if-equal "octal" 65 #o101)
 (pass-if-equal "hex" 257 #x101)
 
+(pass-if-equal "negate" #t ((negate eq?) 0 1))
+(pass-if-equal "const" 42 ((const 42) 1 2 3 4))
+
 (result 'report)