From 9bef3d330cafda13655e7a02093f1038acc21f2b Mon Sep 17 00:00:00 2001
From: Chris Hanson <org/chris-hanson/cph>
Date: Wed, 28 Mar 2018 21:42:19 -0700
Subject: [PATCH] Make second arg to scons-set! optional.

---
 src/runtime/syntax-constructor.scm | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/runtime/syntax-constructor.scm b/src/runtime/syntax-constructor.scm
index c118e1571..e706fd2d7 100644
--- a/src/runtime/syntax-constructor.scm
+++ b/src/runtime/syntax-constructor.scm
@@ -138,12 +138,14 @@ USA.
    (lambda (close)
      (list (close 'quote-identifier) id))))
 
-(define (scons-set! name value)
+(define (scons-set! name #!optional value)
   (make-open-expr
    (lambda (close)
-     (list (close 'set!)
-	   name
-	   (close-part close value)))))
+     (if (default-object? value)
+	 (list (close 'set!) name)
+	 (list (close 'set!)
+	       name
+	       (close-part close value))))))
 
 (define (let-like keyword)
   (lambda (bindings . body-forms)
-- 
2.25.1