block.scm

; This file is part of Scheme+

;; Copyright 2021 Damien MATTEI

;; 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 <https://www.gnu.org/licenses/>.


(define-syntax $ ;; Warning : used by SRFI 9 : Record too ?
  (syntax-rules ()
    ((_ ev)  ev)
    ((_ ev ...) (begin ev ...))))

;; scheme@(guile-user)> (def bar (& (declare x y) {x <- 1} {y <- 2} (lambda (t) (+ x y t))))
;;
;; (def bar (& (declare x y)
;;             {x <- 1} 
;;             {y <- 2}
;;             (lambda (t) (+ x y t))))
;;
;; scheme@(guile-user)> (bar 7)
;; $2 = 10
(define-syntax &
  (syntax-rules ()
    ((_ ev)  (let () ev)) ;;  there can be a <+ in it expanding with a 'define not allowed in expression context
    ((_ ev ...) (let () ev ...))))


;; then and else do as BEGINners ;-)
(define-syntax then-block
  (syntax-rules ()
    ((_ ev)  ev)
    ((_ ev ...) (begin ev ...))))

(define-syntax else-block
  (syntax-rules ()
    ((_ ev)  ev)
    ((_ ev ...) (begin ev ...))))



;; damned... this one makes syntax enlightning bug in Emacs
;; (define-syntax |
;;   (syntax-rules ()
;;     ((_ ev)  ev)
;;     ((_ ev ...) (begin ev ...))))