;;; -*-scheme-*-

;;; Mes --- Maxwell Equations of Software
;;; Copyright © 2016 Jan Nieuwenhuizen <janneke@gnu.org>
;;;
;;; base.mes: This file is part of Mes.
;;;
;;; Mes 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.
;;;
;;; Mes 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 Mes.  If not, see <http://www.gnu.org/licenses/>.

(define (identity x) x)
(define else #t)

;;; COND based
(define-macro (or . x)
  (cond ;; COND
   ((null? x) #f)
   ((null? (cdr x)) (car x))
   (#t (list 'cond (list (car x)) ;; COND
             (list #t (cons 'or (cdr x)))))))

(define-macro (and . x)
  (cond ((null? x) #t) ;; COND
        ((null? (cdr x)) (car x))
        (#t (list 'cond (list (car x) (cons 'and (cdr x))) ;; COND
                  '(#t #f)))))

(define (not x)
  (cond (x #f) ;; COND
        (#t #t)))

(define (equal? a b) ;; FIXME: only 2 arg
  (cond ((and (null? a) (null? b)) #t) ;; COND
        ((and (pair? a) (pair? b))
         (and (equal? (car a) (car b))
              (equal? (cdr a) (cdr b))))
        ((and (string? a) (string? b))
         (eq? (string->symbol a) (string->symbol b)))
        ((and (vector? a) (vector? b))
         (equal? (vector->list a) (vector->list b)))
        (#t (eq? a b))))

(define (memq x lst)
  (cond ((null? lst) #f) ;; COND
        ((eq? x (car lst)) lst)
        (#t (memq x (cdr lst)))))

(define (map f l . r)
  (cond ((null? l) '()) ;; COND
        ((null? r) (cons (f (car l)) (map f (cdr l))))
        ((null? (cdr r))
         (cons (f (car l) (caar r)) (map f (cdr l) (cdar r))))))

;; IF based
(define-macro (or . x)
  (if (null? x) #f ;; IF
      (if (null? (cdr x)) (car x) ;; IF
          (list 'if (car x) (car x)
                (cons* 'or (cdr x))))))

(define-macro (and . x)
  (if (null? x) #t ;; IF
      (if (null? (cdr x)) (car x) ;; IF
          (list 'if (car x) (cons 'and (cdr x)) ;; IF
                #f))))

(define (not x)
  (if x #f #t))

(define (equal? a b) ;; FIXME: only 2 arg
  (if (and (null? a) (null? b)) #t ;; IF
      (if (and (pair? a) (pair? b))
          (and (equal? (car a) (car b))
               (equal? (cdr a) (cdr b)))
          (if (and (string? a) (string? b)) ;; IF
              (eq? (string->symbol a) (string->symbol b))
              (if (and (vector? a) (vector? b)) ;; IF
                  (equal? (vector->list a) (vector->list b))
                  (eq? a b))))))

(define (memq x lst)
  (if (null? lst) #f ;; IF
      (if (eq? x (car lst)) lst ;; IF
          (memq x (cdr lst)))))

(define guile? (not (pair? (current-module))))

(define (map f l . r)
  (if (null? l) '() ;; IF
      (if (null? r) (cons (f (car l)) (map f (cdr l))) ;; IF
          (if (null? (cdr r)) ;; IF
              (cons (f (car l) (caar r)) (map f (cdr l) (cdar r)))))))

(define-macro (simple-let bindings . rest)
  (cons (cons 'lambda (cons (map car bindings) rest))
        (map cadr bindings)))

(define-macro (let bindings . rest)
  (cons* 'simple-let bindings rest))