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47c8983f08
* module/oop/goops.scm (method): Reimplement as a hygienic macro. This seriously took me like 6 hours to figure out. Allows for lexical specializers: (let ((<x> ...)) (define-method (foo (arg <x>)) ...)). * module/oop/goops/compile.scm (next-method?, compile-make-procedure): Remove these, as `method' does it all now, hygienically.
80 lines
2.9 KiB
Scheme
80 lines
2.9 KiB
Scheme
;;;; Copyright (C) 1999, 2001, 2006 Free Software Foundation, Inc.
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;;;;
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;;;; This library is free software; you can redistribute it and/or
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;;;; modify it under the terms of the GNU Lesser General Public
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;;;; License as published by the Free Software Foundation; either
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;;;; version 2.1 of the License, or (at your option) any later version.
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;;;;
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;;;; This library is distributed in the hope that it will be useful,
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;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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;;;; Lesser General Public License for more details.
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;;;;
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;;;; You should have received a copy of the GNU Lesser General Public
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;;;; License along with this library; if not, write to the Free Software
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;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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;;;;
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;; There are circularities here; you can't import (oop goops compile)
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;; before (oop goops). So when compiling, make sure that things are
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;; kosher.
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(eval-when (compile) (resolve-module '(oop goops)))
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(define-module (oop goops compile)
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:use-module (oop goops)
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:use-module (oop goops util)
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:export (compute-cmethod)
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:no-backtrace
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)
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;;;
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;;; Method entries
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;;;
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(define code-table-lookup
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(letrec ((check-entry (lambda (entry types)
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(if (null? types)
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(and (not (struct? (car entry)))
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entry)
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(and (eq? (car entry) (car types))
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(check-entry (cdr entry) (cdr types)))))))
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(lambda (code-table types)
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(cond ((null? code-table) #f)
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((check-entry (car code-table) types))
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(else (code-table-lookup (cdr code-table) types))))))
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(define (compute-cmethod methods types)
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(or (code-table-lookup (slot-ref (car methods) 'code-table) types)
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(let* ((method (car methods))
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(cmethod (compile-method methods types))
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(entry (append types cmethod)))
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(slot-set! method 'code-table
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(cons entry (slot-ref method 'code-table)))
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cmethod)))
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;;;
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;;; Compiling next methods into method bodies
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;;;
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;;; So, for the reader: there basic idea is that, given that the
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;;; semantics of `next-method' depend on the concrete types being
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;;; dispatched, why not compile a specific procedure to handle each type
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;;; combination that we see at runtime.
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;;;
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;;; In theory we can do much better than a bytecode compilation, because
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;;; we know the *exact* types of the arguments. It's ideal for native
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;;; compilation. A task for the future.
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;;;
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;;; I think this whole generic application mess would benefit from a
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;;; strict MOP.
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(define (compile-method methods types)
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(let ((make-procedure (slot-ref (car methods) 'make-procedure)))
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(if make-procedure
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(make-procedure
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(if (null? methods)
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(lambda args
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(no-next-method (method-generic-function (car methods)) args))
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(compute-cmethod (cdr methods) types)))
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(method-procedure (car methods)))))
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