src/method-aggregate.lisp: Move return-type check into `define-' macro.

It seems a better fit this way.

diff --git a/src/method-aggregate.lisp b/src/method-aggregate.lisp
index 1332e10..9d0a6dd 100644 (file)
--- a/src/method-aggregate.lisp
+++ b/src/method-aggregate.lisp
@@ -179,7 +179,7 @@
      (vars
       &key (codegen (gensym "CODEGEN-"))
           (methods (gensym "METHODS-")))
-     &key properties
+     &key properties return-type
          ((:around around-func) '#'funcall)
          ((:first-method first-method-func) nil firstp)
          ((:methods methods-func) '#'funcall))
@@ -211,6 +211,10 @@
    All of these variables, and the VARS, are available in the functions
    described below.
 
+   If a RETURN-TYPE is given, it's a C-type S-expression: a method is defined
+   on `check-aggregating-message-type' to check the that the message's return
+   type matches RETURN-TYPE.
+
    The AROUND, FIRST-METHOD, and METHODS are function designators (probably
    `lambda' forms) providing pieces of the aggregating behaviour.
 
@@ -233,7 +237,7 @@
    the appropriate direct method and deliver its return value to TARGET,
    which defaults to `:void'."
 
-  (with-gensyms (type msg combvar target arg-names args
+  (with-gensyms (type msg combvar target arg-names args want-type
                 meth targ func call-methfunc
                 aroundfunc fmethfunc methfunc)
     `(progn
@@ -251,6 +255,20 @@
                                    (cadr prop)))
                            properties))))
 
+       ;; If a particular return type is wanted, check that.
+       ,@(and return-type
+             `((defmethod check-aggregating-message-type
+                   ((,msg aggregating-message)
+                    (,combvar (eql ',comb))
+                    (,type c-function-type))
+                 (let ((,want-type (c-type ,return-type)))
+                   (unless (c-type-equal-p (c-type-subtype ,type)
+                                           ,want-type)
+                     (error "Messages with `~(~A~)' combination ~
+                             must return `~A'."
+                            ,combvar ,want-type)))
+                 (call-next-method))))
+
        ;; Define the main kernel-compuation method.
        (defmethod compute-aggregating-message-kernel
           ((,msg aggregating-message) (,combvar (eql ',comb))
@@ -313,30 +331,8 @@
 ;;;--------------------------------------------------------------------------
 ;;; Fixed aggregating method combinations.
 
-(flet ((check (comb want type)
-        (unless (eq (c-type-subtype type) want)
-          (error "Messages with `~A' combination must return `~A'."
-                 (string-downcase comb) want))))
-  (defmethod check-aggregating-message-type
-      ((message aggregating-message)
-       (combination (eql :progn))
-       (type c-function-type))
-    (check combination c-type-void type)
-    (call-next-method))
-  (defmethod check-aggregating-message-type
-      ((message aggregating-message)
-       (combination (eql :and))
-       (type c-function-type))
-    (check combination c-type-int type)
-    (call-next-method))
-  (defmethod check-aggregating-message-type
-      ((message aggregating-message)
-       (combination (eql :or))
-       (type c-function-type))
-    (check combination c-type-int type)
-    (call-next-method)))
-
-(define-aggregating-method-combination :progn (nil))
+(define-aggregating-method-combination :progn (nil)
+  :return-type void)
 
 (define-aggregating-method-combination :sum ((acc val) :codegen codegen)
   :first-method (lambda (invoke)
@@ -373,6 +369,7 @@
                                              (make-set-inst acc val) nil))))
 
 (define-aggregating-method-combination :and ((ret val) :codegen codegen)
+  :return-type int
   :around (lambda (body)
            (codegen-push codegen)
            (deliver-expr codegen ret 0)
@@ -386,6 +383,7 @@
                                              (make-break-inst) nil))))
 
 (define-aggregating-method-combination :or ((ret val) :codegen codegen)
+  :return-type int
   :around (lambda (body)
            (codegen-push codegen)
            (deliver-expr codegen ret 1)