adding file necessary for non-threaded parameters

lib/srfi/39/syntax-no-threads.scm

@@ -0,0 +1,40 @@
+;; param.scm -- SRFI-39 parameters
+;; Copyright (c) 2010-2011 Alex Shinn.  All rights reserved.
+;; BSD-style license: http://synthcode.com/license.txt
+
+(define (parameter-convert param value)
+  (let ((proc (parameter-converter param)))
+    (if (procedure? proc)
+        (proc value)
+        value)))
+
+(define (make-parameter init . o)
+  (let ((conv (and (pair? o) (car o))))
+    (%make-parameter (if conv (conv init) init) conv)))
+
+(define-syntax parameterize
+  (syntax-rules ()
+    ((parameterize ("step")
+                   ((param value p old new) ...)
+                   ()
+                   body)
+     (let ((p param) ...)
+       (let ((old (p)) ...
+             (new (parameter-convert p value)) ...)
+         (dynamic-wind
+          (lambda () (p new) ...)
+          (lambda () . body)
+          (lambda () (p old) ...)))))
+    ((parameterize ("step")
+                   args
+                   ((param value) . rest)
+                   body)
+     (parameterize ("step")
+                   ((param value p old new) . args)
+                   rest
+                   body))
+    ((parameterize ((param value) ...) . body)
+     (parameterize ("step")
+                   ()
+                   ((param value) ...)
+                   body))))