From 49020e72a73adb730143be2dc3c3232fab9fff1e Mon Sep 17 00:00:00 2001
From: Arun Isaac
Date: Tue, 1 Jun 2021 13:55:57 +0530
Subject: Add syntax-lambda**.

* ccwl/utils.scm (syntax-lambda**): New public macro.
---
 ccwl/utils.scm | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/ccwl/utils.scm b/ccwl/utils.scm
index 71bc1fe..d0db51c 100644
--- a/ccwl/utils.scm
+++ b/ccwl/utils.scm
@@ -30,6 +30,7 @@
   #:export (pairify
             plist->alist
             lambda**
+            syntax-lambda**
             mapn
             append-mapn
             foldn))
@@ -134,6 +135,16 @@ for example, be invoked as:
                                    rest (list #,@(map (compose symbol->keyword syntax->datum)
                                                       unary-arguments))))))))))))
 
+(define-syntax-rule (syntax-lambda** formal-args body ...)
+  "Like lambda**, but for syntax objects. This is useful for writing
+macros that accept keyword arguments."
+  (lambda (x)
+    (apply (lambda** formal-args body ...)
+           (with-ellipsis :::
+             (syntax-case x ()
+               ((_ args :::)
+                (unsyntax-keywords #'(args :::))))))))
+
 (define (mapn proc lst)
   "Map the procedure PROC over list LST and return a list containing
 the results. PROC can return multiple values, in which case, an equal
-- 
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