From 5361a105fdcb097def20caa980b1956973810b94 Mon Sep 17 00:00:00 2001
From: David Thompson <dthompson2@worcester.edu>
Date: Mon, 25 Aug 2014 19:28:44 -0400
Subject: Add signal-let and signal-let* forms.

* sly/signal.scm (signal-let, signal-let*): New macros.
---
 sly/signal.scm | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/sly/signal.scm b/sly/signal.scm
index 41dddf2..a3e79c4 100644
--- a/sly/signal.scm
+++ b/sly/signal.scm
@@ -29,6 +29,7 @@
   #:export (signal?
             make-signal
             define-signal
+            signal-let signal-let*
             hook->signal
             signal-ref
             signal-ref-maybe
@@ -167,6 +168,17 @@ be coerced into one."
       ((_ name value)
        #'(define name (make-signal-maybe value))))))
 
+(define-syntax-rule (signal-let ((var signal) ...) body ...)
+  ((lambda (var ...) body ...) (signal-ref signal) ...))
+
+(define-syntax signal-let*
+  (syntax-rules ()
+    ((_ ((var signal)) body ...)
+     (signal-let ((var signal)) body ...))
+    ((_ ((var signal) . rest) body ...)
+     (signal-let ((var signal))
+       (signal-let* rest body ...)))))
+
 ;;;
 ;;; Higher Order Signals
 ;;;
-- 
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