ikarus/scheme/ikarus.enumerations.ss

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;;; Ikarus Scheme -- A compiler for R6RS Scheme.
;;; Copyright (C) 2006,2007,2008 Abdulaziz Ghuloum
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;;;
;;; This program is free software: you can redistribute it and/or modify
;;; it under the terms of the GNU General Public License version 3 as
;;; published by the Free Software Foundation.
;;;
;;; 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/>.
(library (ikarus enumerations)
(export make-enumeration enum-set-universe enum-set-indexer
enum-set-constructor enum-set->list enum-set-member?
enum-set-subset? enum-set=? enum-set-union enum-set-difference
enum-set-intersection enum-set-complement enum-set-projection)
(import
(except (ikarus)
make-enumeration enum-set-universe enum-set-indexer
enum-set-constructor enum-set->list enum-set-member?
enum-set-subset? enum-set=? enum-set-union enum-set-difference
enum-set-intersection enum-set-complement
enum-set-projection))
(define-record-type enum
(fields g univ values)
(opaque #t) (sealed #t)
(nongenerative))
(define (make-enumeration ls)
(unless (and (list? ls) (for-all symbol? ls))
(die 'make-enumeration "not a list of symbols" ls))
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(make-enum (gensym) ls ls))
(define (enum-set-universe x)
(unless (enum? x)
(die 'enum-set-universe "not an enumeration" x))
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(enum-univ x))
(define (enum-set-indexer x)
(unless (enum? x)
(die 'enum-set-indexer "not an enumeration" x))
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(lambda (s)
(unless (symbol? s)
(die 'enum-set-indexer "not a symbol" s))
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(let f ([s s] [i 0] [ls (enum-univ x)])
(cond
[(pair? ls)
(if (eq? s (car ls))
i
(f s (+ i 1) (cdr ls)))]
[else #f]))))
(define (enum-set-constructor x)
(unless (enum? x)
(die 'enum-set-constructor "not an enumeration" x))
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(let ([idx (enum-set-indexer x)])
(lambda (ls)
(unless (and (list? ls) (for-all symbol? ls))
(die 'enum-set-constructor "not a list of symbols" ls))
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(for-each
(lambda (s)
(unless (memq s (enum-univ x))
(die 'enum-set-constructor "not in the universe" s x)))
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ls)
(make-enum (enum-g x) (enum-univ x)
(map car
(list-sort (lambda (a b) (< (cdr a) (cdr b)))
(map (lambda (x) (cons x (idx x)))
ls)))))))
(define (enum-set->list x)
(unless (enum? x)
(die 'enum-set->list "not an enumeration" x))
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(map values (enum-values x)))
(define (enum-set-member? s x)
(if (enum? x)
(if (memq s (enum-values x))
#t
(if (symbol? s)
#f
(die 'enum-set-member? "not a symbol" s)))
(die 'enum-set-member? "not an enumeration" x)))
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(define (enum-set-subset? x1 x2)
(define (subset? s1 s2)
(or (null? s1)
(and (memq (car s1) s2)
(subset? (cdr s1) s2))))
(if (enum? x1)
(if (enum? x2)
(and (subset? (enum-values x1) (enum-values x2))
(or (eq? (enum-g x1) (enum-g x2))
(subset? (enum-univ x1) (enum-univ x2))))
(die 'enum-set-subset? "not an enumeration" x2))
(die 'enum-set-subset? "not an enumeration" x1)))
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(define (enum-set=? x1 x2)
(define (subset? s1 s2)
(or (null? s1)
(and (memq (car s1) s2)
(subset? (cdr s1) s2))))
(if (enum? x1)
(if (enum? x2)
(and (subset? (enum-values x1) (enum-values x2))
(subset? (enum-values x2) (enum-values x1))
(or (eq? (enum-g x1) (enum-g x2))
(and (subset? (enum-univ x1) (enum-univ x2))
(subset? (enum-univ x2) (enum-univ x1)))))
(die 'enum-set=? "not an enumeration" x2))
(die 'enum-set=? "not an enumeration" x1)))
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(define (enum-set-op x1 x2 who combine)
(if (enum? x1)
(if (enum? x2)
(let ([g (enum-g x1)] [u (enum-univ x1)])
(if (eq? g (enum-g x2))
(make-enum g u (combine u (enum-values x1) (enum-values x2)))
(die who
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"enum sets have different enumeration types" x1 x2)))
(die who "not an enumeration" x2))
(die who "not an enumeration" x1)))
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(define (enum-set-union x1 x2)
(define (union u s1 s2)
(if (pair? s1)
(if (pair? s2)
(let ([x (car u)])
(if (eq? x (car s1))
(cons x
(union (cdr u) (cdr s1)
(if (eq? x (car s2)) (cdr s2) s2)))
(if (eq? x (car s2))
(cons x (union (cdr u) s1 (cdr s2)))
(union (cdr u) s1 s2))))
s1)
s2))
(enum-set-op x1 x2 'enum-set-union union))
(define (enum-set-intersection x1 x2)
(define (intersection u s1 s2)
(if (pair? s1)
(if (pair? s2)
(let ([x (car u)])
(if (eq? x (car s1))
(if (eq? x (car s2))
(cons x (intersection (cdr u) (cdr s1) (cdr s2)))
(intersection (cdr u) (cdr s1) s2))
(intersection (cdr u) s1
(if (eq? x (car s2)) (cdr s2) s2))))
'())
'()))
(enum-set-op x1 x2 'enum-set-intersection intersection))
(define (enum-set-difference x1 x2)
(define (difference u s1 s2)
(if (pair? s1)
(if (pair? s2)
(let ([x (car u)])
(if (eq? x (car s1))
(if (eq? x (car s2))
(difference (cdr u) (cdr s1) (cdr s2))
(cons x (difference (cdr u) (cdr s1) s2)))
(difference (cdr u) s1
(if (eq? x (car s2)) (cdr s2) s2))))
s1)
'()))
(enum-set-op x1 x2 'enum-set-difference difference))
(define (enum-set-complement x)
(define (complement u s)
(if (pair? s)
(let ([x (car u)])
(if (eq? x (car s))
(complement (cdr u) (cdr s))
(cons x (complement (cdr u) s))))
u))
(if (enum? x)
(let ([g (enum-g x)] [u (enum-univ x)])
(make-enum g u (complement u (enum-values x))))
(die 'enum-set-complement "not an enumeration" x)))
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(define (enum-set-projection x1 x2)
(define (combine u s)
(if (pair? u)
(let ([x (car u)])
(if (memq x s)
(cons x (combine (cdr u) s))
(combine (cdr u) s)))
'()))
(if (enum? x1)
(if (enum? x2)
(let ([g (enum-g x2)])
(if (eq? g (enum-g x1))
x1
(let ([u (enum-univ x2)] [s (enum-values x1)])
(if (null? s)
(make-enum g u '())
(make-enum g u (combine u s))))))
(die 'enum-set-projection "not an enumeration" x2))
(die 'enum-set-projection "not an enumeration" x1)))
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)
#!eof
(define (trace-equal? x y) (equal? x y))
(assert
(trace-equal?
(let* ([e (make-enumeration '(red green blue))]
[i (enum-set-indexer e)])
(list (i 'red) (i 'green) (i 'blue) (i 'yellow)))
'(0 1 2 #f)))
(assert
(trace-equal?
(let* ([e (make-enumeration '(red green blue))]
[c (enum-set-constructor e)])
(enum-set->list (c '(blue red))))
'(red blue)))
(assert
(trace-equal?
(let* ([e (make-enumeration '(red green blue))]
[c (enum-set-constructor e)])
(list
(enum-set-member? 'blue (c '(red blue)))
(enum-set-member? 'green (c '(red blue)))
(enum-set-subset? (c '(red blue)) e)
(enum-set-subset? (c '(red blue)) (c '(blue red)))
(enum-set-subset? (c '(red blue)) (c '(red)))
(enum-set=? (c '(red blue)) (c '(blue red)))))
'(#t #f #t #t #f #t)))
(assert
(trace-equal?
(let* ([e (make-enumeration '(red green blue))]
[c (enum-set-constructor e)])
(list
(enum-set->list (enum-set-union (c '(blue)) (c '(red))))
(enum-set->list (enum-set-intersection (c '(red green)) (c '(red blue))))
(enum-set->list (enum-set-difference (c '(red green)) (c '(red blue))))
(enum-set->list (enum-set-complement (c '(red))))))
'((red blue) (red) (green) (green blue))))
(assert
(trace-equal?
(let* ([e1 (make-enumeration '(red green blue black))]
[e2 (make-enumeration '(red black white))])
(enum-set->list (enum-set-projection e1 e2)))
'(red black)))
#!eof
(define-condition-type &c &condition
make-c c?
(x c-x))
(pretty-print (make-c 'hello))
(assert (c? (make-c 'hello)))
(assert (condition? (make-c 'hello)))
(pretty-print (record-type-descriptor &no-nans))
(assert (no-nans-violation? (make-no-nans-violation)))
(pretty-print
(condition
(condition
((record-constructor (record-constructor-descriptor &message))
"Hello")
(condition)
(condition (make-message-condition "hi"))
(make-message-condition "there"))))