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;;;; "syntest2.scm" Test macros.
;; Copyright (C) 2000, 2001, 2002 Free Software Foundation, Inc.
;;
;; 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/>.
(require 'macro)
;; Redefine some derived special forms.
(define-syntax let
(syntax-rules ()
((let ((?name ?val) ...) . ?body)
((lambda (?name ...) . ?body) ?val ...))
((let ?proc ((?name ?val) ...) . ?body)
(let ((?proc #f)
(?name ?val) ...)
(set! ?proc (lambda (?name ...) . ?body))
(?proc ?name ...)))))
(define-syntax let*
(syntax-rules ()
((let* () . ?body)
((lambda () . ?body)))
((let* ((?name ?val)) . ?body)
((lambda (?name) . ?body) ?val))
((let* ((?name ?val) ?binding ...) . ?body)
(let* ((?name ?val))
(let* (?binding ...) . ?body)))))
(define-syntax letrec
(syntax-rules ()
((letrec ((?name ?val) ...) . ?body)
(let ((?name #f) ...)
(set! ?name ?val) ...
(let () . ?body)))))
(define-syntax and
(syntax-rules ()
((and) #t)
((and ?exp)
(let ((x ?exp))
(if x x #f)))
((and ?exp . ?rest)
(let ((x ?exp))
(if x (and . ?rest) #f)))))
(define-syntax or
(syntax-rules ()
((or) #f)
((or ?exp)
(let ((x ?exp))
(if x x #f)))
((or ?exp . ?rest)
(let ((x ?exp))
(if x x (or . ?rest))))))
(define (force promise)
(promise))
(define (make-promise proc)
(let ((result #f))
(lambda ()
(if result (car result)
(let ((x (proc)))
(if result (car result)
(begin (set! result (list x))
x)))))))
(define-syntax delay
(syntax-rules ()
((delay ?expr)
(make-promise (lambda () ?expr)))))
(define-syntax do
(syntax-rules ()
((do ((?name ?init . ?step) ...)
(?test . ?result)
?body ...)
(let-syntax ((do-step (syntax-rules ()
((do-step ?n) ?n)
((do-step ?n ?s) ?s)))
(do-result (syntax-rules ()
((do-result) (if #f #f))
((do-result . ?r) (begin . ?r)))))
(let loop ((?name ?init) ...)
(if ?test
(do-result . ?result)
(begin ?body ...
(loop (do-step ?name . ?step) ...))))))))
(define-syntax case
(syntax-rules (else)
((case ?x (else . ?conseq))
(begin . ?conseq))
((case ?x (?lst . ?conseq))
(if (memv ?x '?lst) (begin . ?conseq)))
((case ?x (?lst . ?conseq) . ?rest)
(if (memv ?x '?lst)
(begin . ?conseq)
(case ?x . ?rest)))))
(define-syntax cond
(syntax-rules (else =>)
((cond ?clause0 . ?clauses)
(letrec-syntax
((cond-aux
(syntax-rules (else =>)
((cond-aux) (if #f #f))
((cond-aux (else . ?conseq))
(begin . ?conseq))
((cond-aux (?test => ?proc) . ?rest)
(let ((val ?test))
(if val (?proc val) (cond-aux . ?rest))))
((cond-aux (?test) . ?rest)
(or ?test (cond-aux . ?rest)))
((cond-aux (?test . ?conseq) . ?rest)
(if ?test (begin . ?conseq) (cond-aux . ?rest))))))
(cond-aux ?clause0 . ?clauses)))))
;; This may fail if you redefine CONS, LIST, APPEND, or LIST->VECTOR
;; It uses the (... ...) escape.
;; All forms are evaluated inside a LETREC-SYNTAX body (is this a problem?).
(define-syntax quasiquote
(syntax-rules ()
((_ ?template)
(letrec-syntax
((qq
(syntax-rules (unquote unquote-splicing quasiquote)
((_ (unquote ?form) ())
?form)
((_ (unquote ?form) (?depth))
(list 'unquote (qq ?form ?depth)))
((_ (quasiquote ?form) ?depth)
(list 'quasiquote (qq ?form (?depth))))
((_ ((unquote-splicing ?form) . ?rest) ())
(append ?form (qq ?rest ())))
((_ ((unquote-splicing ?form) . ?rest) (?depth))
(append (list 'unquote-splicing (qq ?form ?depth))
(qq ?rest (?depth))))
((_ (?car . ?cdr) ?depth)
(cons (qq ?car ?depth) (qq ?cdr ?depth)))
((_ #(?elt (... ...)) ?depth)
(list->vector (qq (?elt (... ...)) ?depth)))
((_ ?atom ?depth)
'?atom))))
(qq ?template ())))))
;;(load "r4rstest.scm")
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