X-Git-Url: https://git.jsancho.org/?a=blobdiff_plain;f=gacela_misc.lisp;h=bd7027a182b4fcbf773ad84f203e26e02e91faca;hb=15dc6f156f90086f1f82655b43183f0d8647fa0e;hp=8a7c2e433242b551ee3fbc6c2c229d142aaf436a;hpb=6b5631c92ca29a80af99d228b3fe346c5b5e8eee;p=gacela.git

diff --git a/gacela_misc.lisp b/gacela_misc.lisp
index 8a7c2e4..bd7027a 100755
--- a/gacela_misc.lisp
+++ b/gacela_misc.lisp
@@ -14,7 +14,6 @@
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-
 (in-package :gacela)
 
 (defconstant INFINITY MOST-POSITIVE-LONG-FLOAT)
@@ -69,6 +68,38 @@
 			(t (power (* p 2) n)))))
 	  (power 1 n)))
 
+(defmacro secure-block (output-stream &rest forms)
+  (let ((error-handler #'si::universal-error-handler))
+    `(block secure
+       (defun si::universal-error-handler (error-name correctable function-name continue-format-string error-format-string &rest args)
+	 ,(when output-stream
+	    `(write-line
+	      (cond ((eq error-name :WRONG-TYPE-ARGUMENT) (string error-name))
+		    (t error-format-string))
+	      ,output-stream))
+	 (setf (symbol-function 'si::universal-error-handler) ,error-handler)
+	 (return-from secure))
+       (let (result-eval)
+	 (setq result-eval (progn ,@forms))
+	 (setf (symbol-function 'si::universal-error-handler) ,error-handler)
+	 result-eval))))
+
+(defmacro persistent-let (name vars &rest forms)
+  (labels ((get-vars (vars)
+		     (cond ((null vars) nil)
+			   (t (cons (if (consp (car vars)) (caar vars) (car vars))
+				    (get-vars (cdr vars)))))))
+   
+	  `(let ,(cond ((functionp name)
+			(let ((old-vars (funcall name)))
+			  (cond ((equal (get-vars vars) (get-vars old-vars)) old-vars)
+				(t vars))))
+		       (t vars))
+	     (defun ,name ()
+	       ,(let ((lvars (get-vars vars)))
+		  `(mapcar (lambda (x y) (list x y)) ',lvars ,(cons 'list lvars))))
+	     ,@forms)))
+
 ;Geometry
 (defun dotp (dot)
   (match-pattern dot '(0 0)))