use more specific exceptions0.9.1

1 files changed, 5 insertions, 6 deletions

diff --git a/lowlevel.scm b/lowlevel.scm
index 21bfba8..e6bb9c5 100644
--- a/lowlevel.scm
+++ b/lowlevel.scm
@@ -102,6 +102,10 @@ C_return(closure);
   ;; does not exist. This relies on an undocumented internal function,
   ;; although it could be implemented with documented functions.
   (cond
+    ((not (procedure? proc)) (abort
+                              (make-property-condition 'type
+                                                       'message
+                                                       "not a procedure")))
     ((##sys#lambda-decoration proc decoration-is-tag?) => cdr)
     (else #f)))
 
@@ -113,18 +117,13 @@ C_return(closure);
   ;; Return a new closure object that is tagged, has all of its previous
   ;; tags except that `key` maps to `value`.
   (cond
-    ((not (procedure? proc)) (raise
-                              (make-property-condition '(srfi-259 assertion-violation)
-                                                       'message
-                                                       "not a procedure"
-                                                       'arguments
-                                                       (list proc key value))))
     ((get-mapping proc)
      => (lambda (oldmap)
           (set-signifier-pair proc
                               unique-symbol
                               (make-signifier
                                (fxmapping-set oldmap key value)))))
+    ;; get-mapping will test if `proc` is a procedure
     (else (create/signifier-pair proc (make-signifier
                                        (fxmapping key value))))))