381 lines
9.5 KiB
Scheme
381 lines
9.5 KiB
Scheme
; -*- Mode: Scheme; Syntax: Scheme; Package: Scheme; -*-
|
||
; Copyright (c) 1993, 1994 Richard Kelsey and Jonathan Rees. See file COPYING.
|
||
|
||
|
||
; This is file base.scm.
|
||
|
||
;;;; Fundamental definitions
|
||
|
||
; Order of appearance is approximately that of the Revised^4 Report.
|
||
|
||
; Booleans
|
||
|
||
(define (not x) (if x #f #t))
|
||
(define (boolean? x) (or (eq? x #t) (eq? x #f)))
|
||
|
||
; Equality
|
||
|
||
(define (eqv? x y)
|
||
(or (eq? x y)
|
||
(and (number? x)
|
||
(number? y)
|
||
(eq? (exact? x) (exact? y))
|
||
(= x y))))
|
||
|
||
(define (equal? obj1 obj2)
|
||
(cond ((eqv? obj1 obj2) #t)
|
||
((pair? obj1)
|
||
(and (pair? obj2)
|
||
(equal? (car obj1) (car obj2))
|
||
(equal? (cdr obj1) (cdr obj2))))
|
||
((string? obj1)
|
||
(and (string? obj2)
|
||
(string=? obj1 obj2)))
|
||
((vector? obj1)
|
||
(and (vector? obj2)
|
||
(let ((z (vector-length obj1)))
|
||
(and (= z (vector-length obj2))
|
||
(let loop ((i 0))
|
||
(cond ((= i z) #t)
|
||
((equal? (vector-ref obj1 i) (vector-ref obj2 i))
|
||
(loop (+ i 1)))
|
||
(else #f)))))))
|
||
(else #f)))
|
||
|
||
; Simple number stuff
|
||
|
||
(define (> x y) (< y x))
|
||
(define (<= x y) (not (< y x)))
|
||
(define (>= x y) (not (< x y)))
|
||
|
||
(define (max first . rest)
|
||
(reduce (lambda (x y) (if (< x y) y x))
|
||
first
|
||
rest))
|
||
(define (min first . rest)
|
||
(reduce (lambda (x y) (if (< x y) x y))
|
||
first
|
||
rest))
|
||
|
||
(define (abs n) (if (< n 0) (- 0 n) n))
|
||
|
||
(define (zero? x) (= x 0))
|
||
(define (positive? x) (< 0 x))
|
||
(define (negative? x) (< x 0))
|
||
|
||
(define (even? n) (= 0 (remainder n 2)))
|
||
(define (odd? n) (not (even? n)))
|
||
|
||
; Lists
|
||
|
||
(define (caar x) (car (car x)))
|
||
(define (cadr x) (car (cdr x)))
|
||
(define (cdar x) (cdr (car x)))
|
||
(define (cddr x) (cdr (cdr x)))
|
||
|
||
(define (caaar x) (caar (car x)))
|
||
(define (caadr x) (caar (cdr x)))
|
||
(define (cadar x) (cadr (car x)))
|
||
(define (caddr x) (cadr (cdr x)))
|
||
(define (cdaar x) (cdar (car x)))
|
||
(define (cdadr x) (cdar (cdr x)))
|
||
(define (cddar x) (cddr (car x)))
|
||
(define (cdddr x) (cddr (cdr x)))
|
||
|
||
(define (caaaar x) (caaar (car x)))
|
||
(define (caaadr x) (caaar (cdr x)))
|
||
(define (caadar x) (caadr (car x)))
|
||
(define (caaddr x) (caadr (cdr x)))
|
||
(define (cadaar x) (cadar (car x)))
|
||
(define (cadadr x) (cadar (cdr x)))
|
||
(define (caddar x) (caddr (car x)))
|
||
(define (cadddr x) (caddr (cdr x)))
|
||
(define (cdaaar x) (cdaar (car x)))
|
||
(define (cdaadr x) (cdaar (cdr x)))
|
||
(define (cdadar x) (cdadr (car x)))
|
||
(define (cdaddr x) (cdadr (cdr x)))
|
||
(define (cddaar x) (cddar (car x)))
|
||
(define (cddadr x) (cddar (cdr x)))
|
||
(define (cdddar x) (cdddr (car x)))
|
||
(define (cddddr x) (cdddr (cdr x)))
|
||
|
||
(define (null? x) (eq? x '()))
|
||
|
||
(define (list . l) l)
|
||
|
||
(define (length l)
|
||
(reduce (lambda (ignore n) (+ n 1)) 0 l))
|
||
|
||
(define (append . lists)
|
||
(if (null? lists)
|
||
'()
|
||
(let recur ((lists lists))
|
||
(if (null? (cdr lists))
|
||
(car lists)
|
||
(reduce cons (recur (cdr lists)) (car lists))))))
|
||
|
||
(define (reverse list)
|
||
(append-reverse list '()))
|
||
|
||
(define (append-reverse list seed)
|
||
(if (null? list)
|
||
seed
|
||
(append-reverse (cdr list) (cons (car list) seed))))
|
||
|
||
(define (list-tail l i)
|
||
(cond ((= i 0) l)
|
||
(else (list-tail (cdr l) (- i 1)))))
|
||
|
||
(define (list-ref l k)
|
||
(car (list-tail l k)))
|
||
|
||
(define (mem pred)
|
||
(lambda (obj l)
|
||
(let loop ((l l))
|
||
(cond ((null? l) #f)
|
||
((pred obj (car l)) l)
|
||
(else (loop (cdr l)))))))
|
||
|
||
(define memq (mem eq?))
|
||
(define memv (mem eqv?))
|
||
(define member (mem equal?))
|
||
|
||
(define (ass pred)
|
||
(lambda (obj l)
|
||
(let loop ((l l))
|
||
(cond ((null? l) #f)
|
||
((pred obj (caar l)) (car l))
|
||
(else (loop (cdr l)))))))
|
||
|
||
;(define assq (ass eq?))
|
||
(define assv (ass eqv?))
|
||
(define assoc (ass equal?))
|
||
|
||
; Bummed version. Pretend that you didn't see this.
|
||
|
||
(define (assq x l)
|
||
(cond ((null? l) #f)
|
||
((eq? x (caar l)) (car l))
|
||
(else (assq x (cdr l)))))
|
||
|
||
(define (list? l) ;New in R4RS
|
||
(let recur ((l l) (lag l)) ;Cycle detection
|
||
(or (null? l)
|
||
(and (pair? l)
|
||
(or (null? (cdr l))
|
||
(and (pair? (cdr l))
|
||
(not (eq? (cdr l) lag))
|
||
(recur (cddr l) (cdr lag))))))))
|
||
|
||
; Characters
|
||
|
||
(define (char>? x y) (char<? y x))
|
||
(define (char>=? x y) (not (char<? x y)))
|
||
(define (char<=? x y) (not (char>? x y)))
|
||
|
||
(define (char-whitespace? c)
|
||
(if (memq (char->ascii c) ascii-whitespaces) #t #f))
|
||
|
||
(define (char-lower-case? c)
|
||
(and (char>=? c #\a)
|
||
(char<=? c #\z)))
|
||
|
||
(define (char-upper-case? c)
|
||
(and (char>=? c #\A)
|
||
(char<=? c #\Z)))
|
||
|
||
(define (char-numeric? c)
|
||
(and (char>=? c #\0)
|
||
(char<=? c #\9)))
|
||
|
||
(define (char-alphabetic? c)
|
||
(or (char-upper-case? c)
|
||
(char-lower-case? c)))
|
||
|
||
(define char-case-delta
|
||
(- (char->ascii #\a) (char->ascii #\A)))
|
||
|
||
(define (char-upcase c)
|
||
(if (char-lower-case? c)
|
||
(ascii->char (- (char->ascii c) char-case-delta))
|
||
c))
|
||
|
||
(define (char-downcase c)
|
||
(if (char-upper-case? c)
|
||
(ascii->char (+ (char->ascii c) char-case-delta))
|
||
c))
|
||
|
||
(define (char-ci-compare pred)
|
||
(lambda (c1 c2) (pred (char-upcase c1) (char-upcase c2))))
|
||
(define char-ci=? (char-ci-compare char=?))
|
||
(define char-ci<? (char-ci-compare char<?))
|
||
(define char-ci<=? (char-ci-compare char<=?))
|
||
(define char-ci>? (char-ci-compare char>?))
|
||
(define char-ci>=? (char-ci-compare char>=?))
|
||
|
||
|
||
; Strings
|
||
|
||
(define (string . rest)
|
||
(list->string rest))
|
||
|
||
(define (substring s start end)
|
||
(let ((new-string (make-string (- end start) #\space)))
|
||
(do ((i start (+ i 1))
|
||
(j 0 (+ j 1)))
|
||
((= i end) new-string)
|
||
(string-set! new-string j (string-ref s i)))))
|
||
|
||
(define (string-append . strings)
|
||
(let ((len (reduce (lambda (s n) (+ (string-length s) n)) 0 strings)))
|
||
(let ((new-string (make-string len #\space)))
|
||
(let loop ((s strings)
|
||
(i 0))
|
||
(if (null? s)
|
||
new-string
|
||
(let* ((string (car s))
|
||
(l (string-length string)))
|
||
(do ((j 0 (+ j 1))
|
||
(i i (+ i 1)))
|
||
((= j l) (loop (cdr s) i))
|
||
(string-set! new-string i (string-ref string j)))))))))
|
||
|
||
(define (string->list v)
|
||
(let ((z (string-length v)))
|
||
(do ((i (- z 1) (- i 1))
|
||
(l '() (cons (string-ref v i) l)))
|
||
((< i 0) l))))
|
||
|
||
(define (list->string l)
|
||
(let ((v (make-string (length l) #\space)))
|
||
(do ((i 0 (+ i 1))
|
||
(l l (cdr l)))
|
||
((null? l) v)
|
||
(string-set! v i (car l)))))
|
||
|
||
; comes from low-level package ...
|
||
;(define (string-copy s)
|
||
; (let ((z (string-length s)))
|
||
; (let ((copy (make-string z #\space)))
|
||
; (let loop ((i 0))
|
||
; (cond ((= i z) copy)
|
||
; (else
|
||
; (string-set! copy i (string-ref s i))
|
||
; (loop (+ i 1))))))))
|
||
|
||
(define (string-fill! v x)
|
||
(let ((z (string-length v)))
|
||
(do ((i 0 (+ i 1)))
|
||
((= i z) (unspecific))
|
||
(string-set! v i x))))
|
||
|
||
(define (make-string=? char=?)
|
||
(lambda (s1 s2)
|
||
(let ((z (string-length s1)))
|
||
(and (= z (string-length s2))
|
||
(let loop ((i 0))
|
||
(cond ((= i z) #t)
|
||
((char=? (string-ref s1 i) (string-ref s2 i))
|
||
(loop (+ i 1)))
|
||
(else #f)))))))
|
||
|
||
;(define string=? (make-string=? char=?)) -- VM implements this
|
||
(define string-ci=? (make-string=? char-ci=?))
|
||
|
||
(define (make-string<? char<? char=?)
|
||
(lambda (s1 s2)
|
||
(let ((z1 (string-length s1))
|
||
(z2 (string-length s2)))
|
||
(let ((z (min z1 z2)))
|
||
(let loop ((i 0))
|
||
(if (= i z)
|
||
(< z1 z2)
|
||
(let ((c1 (string-ref s1 i))
|
||
(c2 (string-ref s2 i)))
|
||
(or (char<? c1 c2)
|
||
(and (char=? c1 c2)
|
||
(loop (+ i 1)))))))))))
|
||
|
||
(define string<? (make-string<? char<? char=?))
|
||
(define string-ci<? (make-string<? char-ci<? char-ci=?))
|
||
|
||
(define (string>? s1 s2) (string<? s2 s1))
|
||
(define (string<=? s1 s2) (not (string>? s1 s2)))
|
||
(define (string>=? s1 s2) (not (string<? s1 s2)))
|
||
|
||
(define (string-ci>? s1 s2) (string-ci<? s2 s1))
|
||
(define (string-ci<=? s1 s2) (not (string-ci>? s1 s2)))
|
||
(define (string-ci>=? s1 s2) (not (string-ci<? s1 s2)))
|
||
|
||
; Vectors
|
||
|
||
(define (vector . l)
|
||
(list->vector l))
|
||
|
||
(define (vector->list v)
|
||
(do ((i (- (vector-length v) 1) (- i 1))
|
||
(l '() (cons (vector-ref v i) l)))
|
||
((< i 0) l)))
|
||
|
||
(define (list->vector l)
|
||
(let ((v (make-vector (length l) #f)))
|
||
(do ((i 0 (+ i 1))
|
||
(l l (cdr l)))
|
||
((null? l) v)
|
||
(vector-set! v i (car l)))))
|
||
|
||
(define (vector-fill! v x)
|
||
(let ((z (vector-length v)))
|
||
(do ((i 0 (+ i 1)))
|
||
((= i z) (unspecific))
|
||
(vector-set! v i x))))
|
||
|
||
; Control features
|
||
|
||
(define (map proc first . rest)
|
||
(if (null? rest)
|
||
(map1 proc first)
|
||
(map2+ proc first rest)))
|
||
|
||
(define (map1 proc l)
|
||
;; (reduce (lambda (x l) (cons (proc x) l)) '() l)
|
||
(if (null? l)
|
||
'()
|
||
(cons (proc (car l)) (map1 proc (cdr l)))))
|
||
|
||
(define (map2+ proc first rest)
|
||
(if (or (null? first)
|
||
(any null? rest))
|
||
'()
|
||
(cons (apply proc (cons (car first) (map1 car rest)))
|
||
(map2+ proc (cdr first) (map1 cdr rest)))))
|
||
|
||
(define (for-each proc first . rest)
|
||
(let loop ((first first) (rest rest))
|
||
(if (or (null? first)
|
||
(any null? rest))
|
||
(unspecific)
|
||
(begin (apply proc (cons (car first) (map car rest)))
|
||
(loop (cdr first) (map cdr rest))))))
|
||
|
||
|
||
; Promises.
|
||
|
||
(define-syntax delay
|
||
(syntax-rules ()
|
||
((delay ?exp) (make-promise (lambda () ?exp)))))
|
||
|
||
(define (make-promise thunk-then-result)
|
||
(let ((already-run? #f)
|
||
(started? #f))
|
||
(lambda ()
|
||
(cond ((not already-run?)
|
||
(if started? (warn "recursive force" thunk-then-result))
|
||
(set! started? #t)
|
||
(set! thunk-then-result (thunk-then-result))
|
||
(set! already-run? #t)))
|
||
thunk-then-result)))
|
||
|
||
(define (force promise)
|
||
(promise))
|