adding (srfi 154)

lib/srfi/154.scm

@@ -0,0 +1,53 @@
+;; Copyright (C) Marc Nieper-Wißkirchen (2017).  All Rights Reserved.
+
+;; Permission is hereby granted, free of charge, to any person
+;; obtaining a copy of this software and associated documentation
+;; files (the "Software"), to deal in the Software without
+;; restriction, including without limitation the rights to use, copy,
+;; modify, merge, publish, distribute, sublicense, and/or sell copies
+;; of the Software, and to permit persons to whom the Software is
+;; furnished to do so, subject to the following conditions:
+
+;; The above copyright notice and this permission notice shall be
+;; included in all copies or substantial portions of the Software.
+
+;; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+;; EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+;; MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+;; NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+;; BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+;; ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+;; CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+;; SOFTWARE.
+
+(define-syntax closed-lambda
+  (syntax-rules ()
+    ((closed-lambda formals body)
+     (let ((dynamic-environment (current-dynamic-environment)))
+       (lambda formals
+         (with-dynamic-environment dynamic-environment (lambda ()
+                                                         body)))))))
+
+(define-record-type <dynamic-environment>
+  (make-dynamic-environment proc)
+  dynamic-environment?
+  (proc dynamic-environment-proc))
+
+
+(define (current-dynamic-environment)
+  (call-with-current-continuation
+   (lambda (return)
+     (let-values
+         (((k thunk)
+           (call-with-current-continuation
+            (lambda (c)
+              (return
+               (make-dynamic-environment (lambda (thunk)
+                                           (call-with-current-continuation
+                                            (lambda (k)
+                                              (c k thunk))))))))))
+       (call-with-values thunk k)))))
+
+
+(define (with-dynamic-environment dynamic-environment thunk)
+  ((dynamic-environment-proc dynamic-environment) thunk))

lib/srfi/154.sld

@@ -0,0 +1,29 @@
+;; Copyright (C) Marc Nieper-Wißkirchen (2017).  All Rights Reserved.
+
+;; Permission is hereby granted, free of charge, to any person
+;; obtaining a copy of this software and associated documentation
+;; files (the "Software"), to deal in the Software without
+;; restriction, including without limitation the rights to use, copy,
+;; modify, merge, publish, distribute, sublicense, and/or sell copies
+;; of the Software, and to permit persons to whom the Software is
+;; furnished to do so, subject to the following conditions:
+
+;; The above copyright notice and this permission notice shall be
+;; included in all copies or substantial portions of the Software.
+
+;; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+;; EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+;; MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+;; NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+;; BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+;; ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+;; CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+;; SOFTWARE.
+
+(define-library (srfi 154)
+  (export dynamic-environment?
+          current-dynamic-environment
+          with-dynamic-environment
+          closed-lambda)
+  (import (scheme base))
+  (include "154.scm"))