From: Christophe Rhodes <csr21@cantab.net>
Date: Fri, 7 Feb 2014 10:05:21 +0000 (+0000)
Subject: call NO-APPLICABLE-METHOD in the appropriate place
X-Git-Tag: els2014-submission~12
X-Git-Url: http://christophe.rhodes.io/gitweb/?a=commitdiff_plain;h=0ec84041118d2b84f0cdb4f3578e63aa1fae6678;p=specializable.git

call NO-APPLICABLE-METHOD in the appropriate place

Otherwise we end up with NO-PRIMARY-METHODs.  We should only compute
an EMF if there are in fact some methods, or at least that seems to be
the current behaviour of SB-MOP:COMPUTE-EFFECTIVE-METHOD-FUNCTION
---

diff --git a/signum-specializer.lisp b/signum-specializer.lisp
index a5d21fa..ab7c0de 100644
--- a/signum-specializer.lisp
+++ b/signum-specializer.lisp
@@ -63,7 +63,10 @@
    (defmethod fact ((n (signum 0))) 1)
    (defmethod fact ((n (signum 1))) (* n (fact (1- n))))
    (assert (eql (fact 6) 720))
-   (assert (eql (fact 6.0) 720.0))))
+   (assert (eql (fact 6.0) 720.0))
+   (defmethod no-applicable-method ((gf (eql #'fact)) &rest args)
+     'gotcha)
+   (assert (eql (fact -6) 'gotcha))))
 
 (eval
  '(progn
diff --git a/specializable.lisp b/specializable.lisp
index ebe4794..1df14d4 100644
--- a/specializable.lisp
+++ b/specializable.lisp
@@ -155,10 +155,12 @@
                             args))))
 
 (defun compute-effective-method-function (gf methods)
-  (let* ((mc (sb-mop:generic-function-method-combination gf))
-         (sb-pcl::*applicable-methods* methods)
-         (em (sb-mop:compute-effective-method gf mc methods)))
-    (sb-pcl::make-effective-method-function gf em)))
+  (if (null methods)
+      (lambda (&rest args) (apply #'no-applicable-method gf args))
+      (let* ((mc (sb-mop:generic-function-method-combination gf))
+             (sb-pcl::*applicable-methods* methods)
+             (em (sb-mop:compute-effective-method gf mc methods)))
+        (sb-pcl::make-effective-method-function gf em))))
 
 ;; new, not in closette
 (defgeneric generalizer-of-using-class (generic-function object))