From 0fe4342c25a3db2f077f0fe9f90abc4394e358c1 Mon Sep 17 00:00:00 2001
From: Ludovic Court`es
Date: Wed, 27 Sep 2006 13:57:53 +0000
Subject: Fixed creation of engines from an engine class.

* src/guile/skribilo/engine.scm (<engine>): Inherit from `<object>' for
  which there exists an `initialize' method.
  (make-engine-class): Use `make-class' rather than just `(make <class> ...)'.
  (engine-class): New.
  (initialize<engine>): Removed.
  (make-instance<engine-class>)[initialize-engine!]: New.
  (make-engine): Don't pass `:customs'.

git-archimport-id: lcourtes@laas.fr--2005-libre/skribilo--engine-classes--1.2--patch-2
---
 src/guile/skribilo/engine.scm | 47 +++++++++++++++++++++++--------------------
 1 file changed, 25 insertions(+), 22 deletions(-)

diff --git a/src/guile/skribilo/engine.scm b/src/guile/skribilo/engine.scm
index 0622e11..163fe06 100644
--- a/src/guile/skribilo/engine.scm
+++ b/src/guile/skribilo/engine.scm
@@ -107,23 +107,10 @@
   (customs		:init-keyword :custom		:init-value '())
   (symbol-table		:init-keyword :symbol-table	:init-value '()))
 
-(define-class <engine> ()
+(define-class <engine> (<object>)
   (customs	:init-keyword :customs	:init-value '())
   :metaclass <engine-class>)
 
-(define-method (compute-cpl (class <engine-class>))
-  ;; Automatically set the class precedence list of <engine> subclasses.
-  (format (current-error-port) "computing CPL for ~a~%" class)
-  (list class <engine> <top>))
-
-(define-method (initialize (engine-class <engine-class>) . args)
-  ;; Set the name of <engine> subclasses.
-  (let ((result (next-method))
-	(ident (slot-ref engine-class 'ident)))
-    (slot-set! engine-class 'name
-	       (symbol-append '<engine: ident '>))
-    result))
-
 
 (define %format format)
 (define* (make-engine-class ident :key (version 'unspecified)
@@ -133,7 +120,11 @@
 				       (symbol-table '())
 				       (custom '())
 				       (info '()))
-  (let ((e (make <engine-class>
+  ;; We use `make-class' from `(oop goops)' (currently undocumented).
+  (let ((e (make-class (list <engine>) '()
+             :metaclass <engine-class>
+             :name (symbol-append '<engine: ident '>)
+
 	     :ident ident :version version :format format
 	     :filter filter :delegate delegate
 	     :symbol-table symbol-table
@@ -169,27 +160,34 @@
 (define (engine? obj)
   (is-a? obj <engine>))
 
+(define (engine-class e)
+  (and (engine? e) (class-of e)))
+
 ;; A mapping of engine classes to hooks.
 (define %engine-instantiate-hook (make-hash-table))
 
-(define-method (initialize (engine <engine>) . args)
-  (format (current-error-port) "initializing engine ~a~%" engine)
-  engine)
-
 (define-method (make-instance (class <engine-class>) . args)
+  (define (initialize-engine! engine)
+    ;; Automatically initialize the `customs' slot of the newly created
+    ;; engine.
+    (let ((init-values (engine-class-customs class)))
+      (slot-set! engine 'customs (map list-copy init-values))
+      engine))
+
   (format #t "making engine of class ~a~%" class)
   (let ((engine (next-method)))
     (if (engine? engine)
-	(let ((hook (hashq-ref %engine-instantiate-hook engine-class)))
+	(let ((hook (hashq-ref %engine-instantiate-hook class)))
 	  (format (current-error-port) "engine made: ~a~%" engine)
+          (initialize-engine! engine)
 	  (if (hook? hook)
 	      (run-hook hook engine class))
 	  engine)
 	engine)))
 
 (define (make-engine engine-class)
-  (make engine-class
-    :customs (list-copy (slot-ref engine-class 'customs))))
+  (make engine-class))
+
 
 ;; Convenience functions.
 
@@ -209,6 +207,11 @@
 	(string=? fmt (engine-format e)))))
 
 
+
+;;;
+;;; Writers.
+;;;
+
 (define (engine-class-add-writer! e ident pred upred opt before action
 				  after class valid)
   ;; Add a writer to engine class E.  If IDENT is a symbol, then it should
-- 
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