| 1 | ;;; -*-lisp-*- |
| 2 | ;;; |
| 3 | ;;; Method combinations |
| 4 | ;;; |
| 5 | ;;; (c) 2009 Straylight/Edgeware |
| 6 | ;;; |
| 7 | |
| 8 | ;;;----- Licensing notice --------------------------------------------------- |
| 9 | ;;; |
| 10 | ;;; This file is part of the Simple Object Definition system. |
| 11 | ;;; |
| 12 | ;;; SOD is free software; you can redistribute it and/or modify |
| 13 | ;;; it under the terms of the GNU General Public License as published by |
| 14 | ;;; the Free Software Foundation; either version 2 of the License, or |
| 15 | ;;; (at your option) any later version. |
| 16 | ;;; |
| 17 | ;;; SOD is distributed in the hope that it will be useful, |
| 18 | ;;; but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 19 | ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 20 | ;;; GNU General Public License for more details. |
| 21 | ;;; |
| 22 | ;;; You should have received a copy of the GNU General Public License |
| 23 | ;;; along with SOD; if not, write to the Free Software Foundation, |
| 24 | ;;; Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 25 | |
| 26 | (cl:in-package #:sod) |
| 27 | |
| 28 | ;;;-------------------------------------------------------------------------- |
| 29 | ;;; Common behaviour. |
| 30 | |
| 31 | (defclass simple-message (basic-message) |
| 32 | () |
| 33 | (:documentation |
| 34 | "Base class for messages with `simple' method combinations. |
| 35 | |
| 36 | A simple method combination is one which has only one method role other |
| 37 | than the `before', `after' and `around' methods provided by BASIC-MESSAGE. |
| 38 | We call these `primary' methods, and the programmer designates them by not |
| 39 | specifying an explicit role. |
| 40 | |
| 41 | If the programmer doesn't define any primary methods then the effective |
| 42 | method is null -- i.e., the method entry pointer shows up as a null |
| 43 | pointer.")) |
| 44 | |
| 45 | (defclass simple-effective-method (basic-effective-method) |
| 46 | ((primary-methods :initarg :primary-methods :initform nil |
| 47 | :type list :reader effective-method-primary-methods)) |
| 48 | (:documentation |
| 49 | "Effective method counterpart to SIMPLE-MESSAGE.")) |
| 50 | |
| 51 | (defgeneric primary-method-class (message) |
| 52 | (:documentation |
| 53 | "Return the name of the primary direct method class for MESSAGE.")) |
| 54 | |
| 55 | (defgeneric simple-method-body (method codegen target) |
| 56 | (:documentation |
| 57 | "Generate the body of a simple effective method. |
| 58 | |
| 59 | The function is invoked on an effective METHOD, with a CODEGEN to which it |
| 60 | should emit code delivering the method's value to TARGET.")) |
| 61 | |
| 62 | (defmethod sod-message-method-class |
| 63 | ((message standard-message) (class sod-class) pset) |
| 64 | (if (get-property pset :role :keyword nil) |
| 65 | (call-next-method) |
| 66 | (primary-method-class message))) |
| 67 | |
| 68 | (defmethod shared-initialize :after |
| 69 | ((method simple-effective-method) slot-names &key direct-methods) |
| 70 | (declare (ignore slot-names)) |
| 71 | (categorize (method direct-methods :bind ((role (sod-method-role method)))) |
| 72 | ((primary (null role)) |
| 73 | (before (eq role :before)) |
| 74 | (after (eq role :after)) |
| 75 | (around (eq role :around))) |
| 76 | (with-slots (primary-methods before-methods after-methods around-methods) |
| 77 | method |
| 78 | (setf primary-methods primary |
| 79 | before-methods before |
| 80 | after-methods (reverse after) |
| 81 | around-methods around)))) |
| 82 | |
| 83 | (defmethod compute-effective-method-entry-functions |
| 84 | ((method standard-effective-method)) |
| 85 | (if (effective-method-primary-methods method) |
| 86 | (call-next-method) |
| 87 | nil)) |
| 88 | |
| 89 | (defmethod compute-effective-method-body |
| 90 | ((method simple-effective-method) codegen target) |
| 91 | (with-slots (message basic-argument-names primary-methods) method |
| 92 | (basic-effective-method-body codegen target method |
| 93 | (lambda (target) |
| 94 | (simple-method-body method |
| 95 | codegen |
| 96 | target))))) |
| 97 | |
| 98 | ;;;-------------------------------------------------------------------------- |
| 99 | ;;; Standard method combination. |
| 100 | |
| 101 | (defclass standard-message (simple-message) |
| 102 | () |
| 103 | (:documentation |
| 104 | "Message class for standard method combination. |
| 105 | |
| 106 | Standard method combination is a simple method combination where the |
| 107 | primary methods are invoked as a delegation chain, from most- to |
| 108 | least-specific.")) |
| 109 | |
| 110 | (defclass standard-effective-method (simple-effective-method) |
| 111 | () |
| 112 | (:documentation |
| 113 | "Effective method counterpart to STANDARD-MESSAGE.")) |
| 114 | |
| 115 | (defmethod primary-method-class ((message standard-message)) |
| 116 | 'delegating-direct-method) |
| 117 | |
| 118 | (defmethod message-effective-method-class ((message standard-message)) |
| 119 | 'standard-effective-method) |
| 120 | |
| 121 | (defmethod simple-method-body |
| 122 | ((method standard-effective-method) codegen target) |
| 123 | (invoke-delegation-chain codegen |
| 124 | target |
| 125 | (effective-method-basic-argument-names method) |
| 126 | (effective-method-primary-methods method) |
| 127 | nil)) |
| 128 | |
| 129 | ;;;----- That's all, folks -------------------------------------------------- |