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guile/module/oop/goops/compile.scm
Andy Wingo b15dea6857 Replace eval-case with eval-when
* module/ice-9/boot-9.scm (eval-when): Replace eval-case with eval-when.
  Eval-when is *much* simpler, and more expressive to boot. Perhaps in
  the future we'll get 'visit and 'revisit too.

* module/ice-9/deprecated.scm (eval-case): Provide mostly-working
  deprecated version of eval-case.

* module/ice-9/boot-9.scm (defmacro, define-macro): Relax condition: we
  can make defmacros that are not at the toplevel now. But in the future
  we should replace this implementation of defmacros with one written in
  syntax-case.
  (define-module, use-modules, use-syntax): Allow at non-toplevel.
  (define-public, defmacro-public, export, re-export): Don't evaluate at
  compile-time, I can't see how that helps things. Allow `export' and
  `re-export' at non-toplevel.

* module/ice-9/getopt-long.scm:
* module/ice-9/i18n.scm:
* module/oop/goops.scm:
* module/oop/goops/compile.scm:
* module/oop/goops/dispatch.scm: Switch to use eval-when, not
  eval-case.

* module/language/scheme/compile-ghil.scm (eval-when): Replace eval-case
  transformer with eval-when transformer. Sooooo much simpler, and it
  will get better once we separate expansion from compilation.

* module/language/scheme/expand.scm (quasiquote): Hm, expand quasiquote
  properly. Not hygienic. Syncase needed.
  (lambda): Handle internal defines with docstrings propertly.
2009-03-06 13:29:13 +01:00

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