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;;; -*- mode: lisp; coding: utf-8 -*-
;;; Étoilisp/Mulklisp, a Common Lisp subset for the Étoilé runtime.
;;; Copyright (C) 2008 Matthias Andreas Benkard.
;;;
;;; This program is free software: you can redistribute it and/or modify
;;; it under the terms of the GNU General Public License as published by
;;; the Free Software Foundation, either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; This program 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
;;; General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with this program. If not, see <http://www.gnu.org/licenses/>.
(in-package #:common-lisp)
(export '(identity constantly complement tagbody go block return-from
return defconstant prog prog* macrolet flet prog1 prog2
labels))
(defun identity (x)
x)
(defun constantly (c)
(lambda (x)
(declare (ignore x))
c))
(defun complement (function)
(lambda (x) (not (funcall function x))))
(defmacro labels ((&rest function-bindings) &body forms)
"Look, ma, I've defined LABELS in terms of FLET!"
`(flet ,(mapcar (lambda (x) `(,(first x) ())) function-bindings)
(%fsetq ,@(mapcan (lambda (x)
`(,(first x) (lambda ,(second x) ,@(rest (rest x)))))
function-bindings))
nil
,@forms))
(defmacro defconstant (name value &optional documentation)
`(setq ,name ,value))
(defmacro prog1 (form &body forms)
(let ((varsym (gensym)))
`(let ((,varsym ,form))
,@forms
,varsym)))
(defmacro prog2 (form1 form2 &body forms)
`(progn
,form1
(prog1 ,form2
,@forms)))
;; FIXME: Should be (EVAL-WHEN (:compile-toplevel) ...).
(unless (boundp '+block-mapping-sym+)
(defconstant +block-mapping-sym+ (gensym "BLOCK-NAME")))
(defmacro #.+block-mapping-sym+ () nil)
(defmacro block (block-name &body body)
(let ((catch-tag (gensym)))
`(macrolet ((,+block-mapping-sym+ ()
`(quote ,(acons ',block-name
',catch-tag
(,+block-mapping-sym+)))))
(catch ',catch-tag
,@body))))
(defmacro return-from (block-name &optional value &environment env)
`(throw ',(cdr (assoc block-name (cadr (macroexpand `(,+block-mapping-sym+)
env))
:test 'eq))
,value))
(defmacro return (&optional value)
`(return-from nil ,value))
;; FIXME: Should be (EVAL-WHEN (:compile-toplevel) ...).
(unless (boundp '+go-tag-function-mapping-sym+)
(defconstant +go-tag-function-mapping-sym+ (gensym "GO-FUNCTION"))
(defconstant +go-tag-catch-tag-mapping-sym+ (gensym "GO-CATCH-TAG")))
(defmacro #.+go-tag-function-mapping-sym+ () nil)
(defmacro #.+go-tag-catch-tag-mapping-sym+ () nil)
(defmacro go (tag &environment env)
`(throw ',(cdr (assoc tag (cadr (macroexpand `(,+go-tag-catch-tag-mapping-sym+)
env))
:test 'eq))
(function ,(cdr (assoc tag (cadr (macroexpand `(,+go-tag-function-mapping-sym+)
env))
:test 'eq)))))
(defmacro tagbody (&body body)
(let* (labels-and-catch-tags
labels-and-functions
(catch-tag (gensym "TAGBODY-CATCH-TAG"))
(block-name (gensym "TAGBODY-BLOCK-NAME"))
(return-value-sym (gensym "TAGBODY-RETURN-VALUE"))
(end-marker (gensym "TAGBODY-END"))
(sections
(mapcon (let (current-label
accumulated-clauses
current-function)
(lambda (clause-and-rest)
(let ((clause (car clause-and-rest))
(rest (cdr clause-and-rest)))
(cond
((atom clause)
(when current-function
(pushq (cons current-label current-function)
labels-and-functions)
(pushq (cons current-label catch-tag)
labels-and-catch-tags))
(let ((old-function current-function))
(setq current-label clause
current-function (gensym "TAGBODY-SECTION"))
(prog1
`((,old-function ()
;; Yes, we generate this even when
;; OLD-FUNCTION is NIL. In this
;; case, though, the LABELS form
;; never sees the definition. Grep
;; for (cddr (first sections)) below
;; in order to see how we make use of
;; the generated lambda form instead.
,@(nreverse accumulated-clauses)
#',current-function)
,@(when (endp rest)
`((,current-function ()
',end-marker))))
(setq accumulated-clauses nil))))
(t (pushq clause accumulated-clauses)
(if (endp rest)
(progn
(when current-function
(pushq (cons current-label current-function)
labels-and-functions)
(pushq (cons current-label catch-tag)
labels-and-catch-tags))
`((,current-function ()
,@(nreverse accumulated-clauses)
',end-marker)))
nil))))))
body)))
`(macrolet ((,+go-tag-catch-tag-mapping-sym+ ()
(list 'quote
(list* ,@(mapcar (lambda (x) (list 'quote x))
labels-and-catch-tags)
(,+go-tag-catch-tag-mapping-sym+))))
(,+go-tag-function-mapping-sym+ ()
(list 'quote
(list* ,@(mapcar (lambda (x) (list 'quote x))
labels-and-functions)
(,+go-tag-function-mapping-sym+)))))
(labels (,@(rest sections))
(block ,block-name
(let (,return-value-sym)
(%loop
(setq ,return-value-sym
(catch ',catch-tag
(if ,return-value-sym
(funcall ,return-value-sym)
(progn ,@(cddr (first sections))))))
(when (eq ,return-value-sym ',end-marker)
(return-from ,block-name nil)))))))))
(defmacro prog (bindings &body body)
;;FIXME: declarations
(let ((declarations nil)
(body body))
`(let ,bindings
,@declarations
(tagbody
,@body))))
(defmacro prog* (bindings &body body)
;;FIXME: declarations
(let ((declarations nil)
(body body))
`(let* ,bindings
,@declarations
(tagbody
,@body))))
(defmacro macrolet (bindings &body body)
`(%macrolet ,(mapcar (lambda (binding)
`(,(car binding)
,@(make-defmacro-body (cadr binding)
(cddr binding))))
bindings)
,@body))
(defmacro flet (bindings &body body)
`(%flet ,(mapcar (lambda (binding)
`(,(car binding)
,@(make-defun-body (cadr binding)
(cddr binding))))
bindings)
,@body))
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