From d145f6df86aca5c0b520f300ce8821e762a9707b Mon Sep 17 00:00:00 2001
From: Mark Wooding <mdw@distorted.org.uk>
Date: Sun, 30 Aug 2015 11:07:21 +0100
Subject: [PATCH] src/class-make-{proto,impl}.lisp: Better choice of default
 message class.

If a combination is specified, use the new `aggregating-message' by
default.
---
 src/class-make-impl.lisp  | 17 ++++++++++-------
 src/class-make-proto.lisp | 13 +++++++------
 2 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/src/class-make-impl.lisp b/src/class-make-impl.lisp
index 1daab39..28c1958 100644
--- a/src/class-make-impl.lisp
+++ b/src/class-make-impl.lisp
@@ -152,13 +152,16 @@
 (defmethod make-sod-message
     ((class sod-class) name type pset &optional location)
   (with-default-error-location (location)
-    (let ((message (make-instance (get-property pset :message-class :symbol
-						'standard-message)
-				  :class class
-				  :name name
-				  :type type
-				  :location (file-location location)
-				  :pset pset)))
+    (let* ((msg-class (or (get-property pset :message-class :symbol)
+			  (and (get-property pset :combination :keyword)
+			       'aggregating-message)
+			  'standard-message))
+	   (message (make-instance msg-class
+				   :class class
+				   :name name
+				   :type type
+				   :location (file-location location)
+				   :pset pset)))
       (with-slots (messages) class
 	(setf messages (append messages (list message)))))))
 
diff --git a/src/class-make-proto.lisp b/src/class-make-proto.lisp
index 01e18eb..c04727c 100644
--- a/src/class-make-proto.lisp
+++ b/src/class-make-proto.lisp
@@ -136,12 +136,13 @@
 
    This is the main constructor function for messages.  This is a generic
    function primarily so that the CLASS can intervene in the construction
-   process.  The default method uses the `:message-class' property
-   (defaulting to `sod-message') to choose a (CLOS) class to instantiate.
-   The message is then constructed by `make-instance' passing the arguments
-   as initargs; further behaviour is left to the standard CLOS instance
-   construction protocol; for example, `sod-message' defines an
-   `:after'-method on `shared-initialize'."))
+   process.  The default method uses the `:message-class' property to choose
+   a (CLOS) class to instantiate; if no such property is provided but a
+   `combination' property is present, then `aggregating-message' is chosen;
+   otherwise `standard-message' is used.  The message is then constructed by
+   `make-instance' passing the arguments as initargs; further behaviour is
+   left to the standard CLOS instance construction protocol; for example,
+   `sod-message' defines an `:after'-method on `shared-initialize'."))
 
 (export 'make-sod-method)
 (defgeneric make-sod-method
-- 
2.11.0