EuLisp is a programming language created in 1985.
| #181on PLDB | 39Years Old |
EuLisp is a statically and dynamically scoped Lisp dialect developed by a loose formation of industrial and academic Lisp users and developers from around Europe. The standardizers intended to create a new Lisp "less encumbered by the past" (compared to Common Lisp), and not so minimalist as Scheme. Another objective was to integrate the object-oriented programming paradigm well. Read more on Wikipedia...
(defmodule hanoi
(syntax (syntax-0)
import (level-0)
export (hanoi))
;;;-------------------------------------------------
;;; Tower definition
;;;-------------------------------------------------
(defconstant *max-tower-height* 10)
(defclass <tower> ()
((id reader: tower-id keyword: id:)
(blocks accessor: tower-blocks)))
(defun build-tower (x n)
(labels ((loop (i res)
(if (= i 0) res
(loop (- i 1) (cons i res)))))
((setter tower-blocks) x (loop n ()))
x))
(defmethod generic-print ((x <tower>) (s <stream>))
(sformat s "#<tower ~a: ~a>" (tower-id x) (tower-blocks x)))
;;;-------------------------------------------------
;;; Access to tower blocks
;;;-------------------------------------------------
(defgeneric push (x y))
(defmethod push ((x <tower>) (y <fpi>))
(let ((blocks (tower-blocks x)))
(if (or (null? blocks) (< y (car blocks)))
((setter tower-blocks) x (cons y blocks))
(error <condition>
(fmt "cannot push block of size ~a on tower ~a" y x)))))
(defgeneric pop (x))
(defmethod pop ((x <tower>))
(let ((blocks (tower-blocks x)))
(if blocks
(progn
((setter tower-blocks) x (cdr blocks))
(car blocks))
(error <condition>
(fmt "cannot pop block from empty tower ~a" x)))))
;;;-------------------------------------------------
;;; Move n blocks from tower x1 to tower x2 using x3 as buffer
;;;-------------------------------------------------
(defgeneric move (n x1 x2 x3))
(defmethod move ((n <fpi>) (x1 <tower>) (x2 <tower>) (x3 <tower>))
(if (= n 1)
(progn
(push x2 (pop x1))
(print x1 nl x2 nl x3 nl nl))
(progn
(move (- n 1) x1 x3 x2)
(move 1 x1 x2 x3)
(move (- n 1) x3 x2 x1))))
;;;-------------------------------------------------
;;; Initialize and run the 'Towers of Hanoi'
;;;-------------------------------------------------
(defun hanoi ()
(let ((x1 (make <tower> id: 0))
(x2 (make <tower> id: 1))
(x3 (make <tower> id: 2)))
(build-tower x1 *max-tower-height*)
(build-tower x2 0)
(build-tower x3 0)
(print x1 nl x2 nl x3 nl nl)
(move *max-tower-height* x1 x2 x3)))
(hanoi)
;;;-------------------------------------------------
) ;; End of module hanoi
;;;-------------------------------------------------| Feature | Supported | Token | Example |
|---|---|---|---|
| Comments | ✓ | ; A comment |
|
| Line Comments | ✓ | ; | ; A comment |
| Multiple Inheritance | ✓ | ||
| Semantic Indentation | X |