From: Javier Sancho <jsf@jsancho.org>
Date: Sun, 3 Nov 2013 14:42:25 +0000 (+0100)
Subject: Improving with-engine
X-Git-Url: https://git.jsancho.org/?p=gacela.git;a=commitdiff_plain;h=2a4f421a74b6e31e7718d206be704f1d42a268a2

Improving with-engine

* src/engine.scm: with-engine now saves current engine for recursive
                  calls and uses engine mutex for exclusive access
---

diff --git a/src/engine.scm b/src/engine.scm
index 6d5e0e7..0770e09 100644
--- a/src/engine.scm
+++ b/src/engine.scm
@@ -94,10 +94,12 @@
 (define-syntax with-engine
   (syntax-rules ()
     ((_ engine body ...)
-     (begin
+     (let ((old-engine (current-engine)))
        (set-current-engine! engine)
-       (let ((res (begin body ...)))
-	 (set-current-engine! #f)
+       (let ((res (with-mutex (engine-mutex engine)
+		    body
+		    ...)))
+	 (set-current-engine! old-engine)
 	 res)))))
 
 (export current-engine