From: Chris Hanson <org/chris-hanson/cph>
Date: Mon, 4 Jun 2001 17:38:50 +0000 (+0000)
Subject: Implement WITH-OPEN-RESOURCE.
X-Git-Tag: 20090517-FFI~2730
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=306d4287a25f6a33e592a8c90bd9f37c48fca296;p=mit-scheme.git

Implement WITH-OPEN-RESOURCE.
---

diff --git a/v7/src/imail/imail-core.scm b/v7/src/imail/imail-core.scm
index 03d9d6b02..b8b80b457 100644
--- a/v7/src/imail/imail-core.scm
+++ b/v7/src/imail/imail-core.scm
@@ -1,6 +1,6 @@
 ;;; -*-Scheme-*-
 ;;;
-;;; $Id: imail-core.scm,v 1.142 2001/06/03 01:42:28 cph Exp $
+;;; $Id: imail-core.scm,v 1.143 2001/06/04 17:38:50 cph Exp $
 ;;;
 ;;; Copyright (c) 1999-2001 Massachusetts Institute of Technology
 ;;;
@@ -470,6 +470,19 @@
 
 (define-generic %open-resource (url))
 
+(define (with-open-resource url procedure)
+  (let ((resource #f))
+    (dynamic-wind (lambda ()
+		    (set! resource (open-resource url))
+		    unspecific)
+		  (lambda () (procedure resource))
+		  (lambda ()
+		    (let ((r resource))
+		      (if r
+			  (begin
+			    (set! resource #f)
+			    (close-resource r #f))))))))
+
 ;; -------------------------------------------------------------------
 ;; Close RESOURCE, freeing up connections, memory, etc.  Subsequent
 ;; use of the resource must work, but may incur a significant time or