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fix rotting indentation, switch to #lang

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svn: r8987
This commit is contained in:
Eli Barzilay 2008-03-16 15:17:50 +00:00
parent 696f8a24ba
commit 38ba4f29e8
12 changed files with 1292 additions and 1409 deletions
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24
collects/srfi/1/alist.ss
View File

@ -32,45 +32,41 @@
;; hold me liable for its use. Please send bug reports to shivers@ai.mit.edu. ;; hold me liable for its use. Please send bug reports to shivers@ai.mit.edu.
;; -Olin ;; -Olin
(module alist #lang mzscheme
mzscheme
(require mzlib/etc (require mzlib/etc
srfi/optional srfi/optional
(only "search.ss" find) (only "search.ss" find)
"filter.ss" "filter.ss"
(rename "fold.ss" s:map map)) (rename "fold.ss" s:map map))
(provide (rename my-assoc assoc) (provide (rename my-assoc assoc)
alist-cons alist-cons
alist-copy alist-copy
alist-delete alist-delete
#;alist-delete!) #;alist-delete!)
;; Extended from R4RS to take an optional comparison argument.
;; Extended from R4RS to take an optional comparison argument. (define my-assoc
(define my-assoc
(opt-lambda (x lis (maybe-= equal?)) (opt-lambda (x lis (maybe-= equal?))
(let ((= maybe-=)) (let ((= maybe-=))
(find (lambda (entry) (= x (car entry))) lis)))) (find (lambda (entry) (= x (car entry))) lis))))
(define (alist-cons key datum alist) (cons (cons key datum) alist)) (define (alist-cons key datum alist) (cons (cons key datum) alist))
(define (alist-copy alist) (define (alist-copy alist)
(s:map (lambda (elt) (cons (car elt) (cdr elt))) (s:map (lambda (elt) (cons (car elt) (cdr elt)))
alist)) alist))
(define alist-delete (define alist-delete
(opt-lambda (key alist (maybe-= equal?)) (opt-lambda (key alist (maybe-= equal?))
(let ((= maybe-=)) (let ((= maybe-=))
(filter (lambda (elt) (not (= key (car elt)))) alist)))) (filter (lambda (elt) (not (= key (car elt)))) alist))))
#; #;
(define alist-delete! (define alist-delete!
(opt-lambda (key alist (maybe-= equal?)) (opt-lambda (key alist (maybe-= equal?))
(let ((= maybe-=)) (let ((= maybe-=))
(filter! (lambda (elt) (not (= key (car elt)))) alist)))) (filter! (lambda (elt) (not (= key (car elt)))) alist))))
)
;;; alist.ss ends here ;;; alist.ss ends here

59
collects/srfi/1/cons.ss
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@ -32,14 +32,13 @@
;; hold me liable for its use. Please send bug reports to shivers@ai.mit.edu. ;; hold me liable for its use. Please send bug reports to shivers@ai.mit.edu.
;; -Olin ;; -Olin
(module cons #lang mzscheme
mzscheme
(require mzlib/etc (require mzlib/etc
srfi/optional srfi/optional
"selector.ss") "selector.ss")
(provide xcons (provide xcons
make-list make-list
list-tabulate list-tabulate
cons* cons*
@ -47,64 +46,57 @@
circular-list circular-list
iota) iota)
;; Occasionally useful as a value to be passed to a fold or other ;; Occasionally useful as a value to be passed to a fold or other
;; higher-order procedure. ;; higher-order procedure.
(define (xcons d a) (cons a d)) (define (xcons d a) (cons a d))
;; Make a list of length LEN.
;; Make a list of length LEN. (define make-list
(define make-list
(opt-lambda (len [elt #f]) (opt-lambda (len [elt #f])
(check-arg (lambda (n) (and (integer? n) (>= n 0))) len 'make-list) (check-arg (lambda (n) (and (integer? n) (>= n 0))) len 'make-list)
(do ((i len (- i 1)) (do ((i len (- i 1))
(ans '() (cons elt ans))) (ans '() (cons elt ans)))
((<= i 0) ans)))) ((<= i 0) ans))))
;; Make a list of length LEN. Elt i is (PROC i) for 0 <= i < LEN.
;; Make a list of length LEN. Elt i is (PROC i) for 0 <= i < LEN. (define (list-tabulate len proc)
(define (list-tabulate len proc)
(check-arg (lambda (n) (and (integer? n) (>= n 0))) len 'list-tabulate) (check-arg (lambda (n) (and (integer? n) (>= n 0))) len 'list-tabulate)
(check-arg procedure? proc 'list-tabulate) (check-arg procedure? proc 'list-tabulate)
(do ((i (- len 1) (- i 1)) (do ((i (- len 1) (- i 1))
(ans '() (cons (proc i) ans))) (ans '() (cons (proc i) ans)))
((< i 0) ans))) ((< i 0) ans)))
;; (cons* a1 a2 ... an) = (cons a1 (cons a2 (cons ... an))) ;; (cons* a1 a2 ... an) = (cons a1 (cons a2 (cons ... an)))
;; (cons* a1) = a1 (cons* a1 a2 ...) = (cons a1 (cons* a2 ...)) ;; (cons* a1) = a1; (cons* a1 a2 ...) = (cons a1 (cons* a2 ...))
;; ;;
;; (cons first (unfold not-pair? car cdr rest values)) ;; (cons first (unfold not-pair? car cdr rest values))
(define (cons* first . rest) (define (cons* first . rest)
(let recur ((x first) (rest rest)) (let recur ((x first) (rest rest))
(if (pair? rest) (if (pair? rest)
(cons x (recur (car rest) (cdr rest))) (cons x (recur (car rest) (cdr rest)))
x))) x)))
(define (list-copy lis)
(define (list-copy lis)
(let recur ((lis lis)) (let recur ((lis lis))
(if (pair? lis) (if (pair? lis)
(cons (car lis) (recur (cdr lis))) (cons (car lis) (recur (cdr lis)))
lis))) lis)))
(define (circular-list val1 . vals)
(define (circular-list val1 . vals)
(let ([ph (make-placeholder #f)]) (let ([ph (make-placeholder #f)])
(placeholder-set! ph (placeholder-set! ph
(cons val1 (cons val1 (let loop ([vals vals])
(let loop ([vals vals])
(if (null? vals) (if (null? vals)
ph ph
(cons (car vals) (cons (car vals) (loop (cdr vals)))))))
(loop (cdr vals)))))))
(make-reader-graph ph))) (make-reader-graph ph)))
;; IOTA count [start step] (start start+step ... start+(count-1)*step)
;; IOTA count [start step] (start start+step ... start+(count-1)*step) (define iota
(define iota
(opt-lambda (count [start 0] [step 1]) (opt-lambda (count [start 0] [step 1])
(check-arg integer? count 'iota) (check-arg integer? count 'iota)
(check-arg number? start 'iota) (check-arg number? start 'iota)
@ -112,12 +104,7 @@
(unless (or (zero? count) (positive? count)) (unless (or (zero? count) (positive? count))
(error 'iota "count expected to be non-negative, got: ~a" count)) (error 'iota "count expected to be non-negative, got: ~a" count))
(let loop ([n 0]) (let loop ([n 0])
(cond (if (= n count) '()
[(= n count) '()] (cons (+ start (* n step)) (loop (add1 n)))))))
[else (cons (+ start (* n step))
(loop (add1 n)))]))))
)
;;; cons.ss ends here ;;; cons.ss ends here

38
collects/srfi/1/delete.ss
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@ -33,40 +33,39 @@
;; hold me liable for its use. Please send bug reports to shivers@ai.mit.edu. ;; hold me liable for its use. Please send bug reports to shivers@ai.mit.edu.
;; -Olin ;; -Olin
(module delete #lang mzscheme
mzscheme
(require mzlib/etc (require mzlib/etc
srfi/optional srfi/optional
"predicate.ss" "predicate.ss"
"filter.ss") "filter.ss")
(provide delete (provide delete
(rename delete delete!) (rename delete delete!)
delete-duplicates delete-duplicates
(rename delete-duplicates delete-duplicates!)) (rename delete-duplicates delete-duplicates!))
(define delete (define delete
(opt-lambda (x lis (maybe-= equal?)) (opt-lambda (x lis (maybe-= equal?))
(let ((= maybe-=)) (let ((= maybe-=))
(filter (lambda (y) (not (= x y))) lis)))) (filter (lambda (y) (not (= x y))) lis))))
#; #;
(define delete! (define delete!
(opt-lambda (x lis (maybe-= equal?)) (opt-lambda (x lis (maybe-= equal?))
(let ((= maybe-=)) (let ((= maybe-=))
(filter! (lambda (y) (not (= x y))) lis)))) (filter! (lambda (y) (not (= x y))) lis))))
;; right-duplicate deletion ;; right-duplicate deletion
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; delete-duplicates delete-duplicates! ;; delete-duplicates delete-duplicates!
;; ;;
;; Beware -- these are N^2 algorithms. To efficiently remove duplicates ;; Beware -- these are N^2 algorithms. To efficiently remove duplicates
;; in long lists, sort the list to bring duplicates together, then use a ;; in long lists, sort the list to bring duplicates together, then use a
;; linear-time algorithm to kill the dups. Or use an algorithm based on ;; linear-time algorithm to kill the dups. Or use an algorithm based on
;; element-marking. The former gives you O(n lg n), the latter is linear. ;; element-marking. The former gives you O(n lg n), the latter is linear.
(define delete-duplicates (define delete-duplicates
(opt-lambda (lis (maybe-= equal?)) (opt-lambda (lis (maybe-= equal?))
(let ((elt= maybe-=)) (let ((elt= maybe-=))
(check-arg procedure? elt= 'delete-duplicates) (check-arg procedure? elt= 'delete-duplicates)
@ -77,8 +76,8 @@
(new-tail (recur (delete x tail elt=)))) (new-tail (recur (delete x tail elt=))))
(if (eq? tail new-tail) lis (cons x new-tail)))))))) (if (eq? tail new-tail) lis (cons x new-tail))))))))
#; #;
(define delete-duplicates! (define delete-duplicates!
(opt-lambda (lis (maybe-= equal?)) (opt-lambda (lis (maybe-= equal?))
(let ((elt= maybe-=)) (let ((elt= maybe-=))
(check-arg procedure? elt= 'delete-duplicates!) (check-arg procedure? elt= 'delete-duplicates!)
@ -89,7 +88,4 @@
(new-tail (recur (delete! x tail elt=)))) (new-tail (recur (delete! x tail elt=))))
(if (eq? tail new-tail) lis (cons x new-tail)))))))) (if (eq? tail new-tail) lis (cons x new-tail))))))))
)
;;; delete.ss ends here ;;; delete.ss ends here

97
collects/srfi/1/filter.ss
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@ -32,32 +32,30 @@
;; hold me liable for its use. Please send bug reports to shivers@ai.mit.edu. ;; hold me liable for its use. Please send bug reports to shivers@ai.mit.edu.
;; -Olin ;; -Olin
(module filter #lang mzscheme
mzscheme
(require mzlib/etc (require mzlib/etc
srfi/optional srfi/optional
"predicate.ss") "predicate.ss"
(require srfi/8/receive) srfi/8/receive)
(provide filter (provide filter
partition partition
remove remove
(rename filter filter!) (rename filter filter!)
(rename partition partition!) (rename partition partition!)
(rename remove remove!)) (rename remove remove!))
;; filter, remove, partition
;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; FILTER, REMOVE, PARTITION and their destructive counterparts do not
;; disorder the elements of their argument.
;; filter, remove, partition ;; This FILTER shares the longest tail of L that has no deleted
;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; elements. If Scheme had multi-continuation calls, they could be
;; FILTER, REMOVE, PARTITION and their destructive counterparts do not ;; made more efficient.
;; disorder the elements of their argument.
;; This FILTER shares the longest tail of L that has no deleted (define (filter pred lis) ; Sleazing with EQ? makes this
;; elements. If Scheme had multi-continuation calls, they could be
;; made more efficient.
(define (filter pred lis) ; Sleazing with EQ? makes this
(check-arg procedure? pred 'filter) ; one faster. (check-arg procedure? pred 'filter) ; one faster.
(let recur ((lis lis)) (let recur ((lis lis))
(if (null-list? lis) lis ; Use NOT-PAIR? to handle dotted lists. (if (null-list? lis) lis ; Use NOT-PAIR? to handle dotted lists.
@ -69,25 +67,20 @@
(cons head new-tail))) (cons head new-tail)))
(recur tail)))))) ; this one can be a tail call. (recur tail)))))) ; this one can be a tail call.
;; This implementation of FILTER!
;; - doesn't cons, and uses no stack;
;; - is careful not to do redundant SET-CDR! writes, as writes to memory are
;; usually expensive on modern machines, and can be extremely expensive on
;; This implementation of FILTER! ;; modern Schemes (e.g., ones that have generational GC's).
;; - doesn't cons, and uses no stack; ;; It just zips down contiguous runs of in and out elts in LIS doing the
;; - is careful not to do redundant SET-CDR! writes, as writes to memory are ;; minimal number of SET-CDR!s to splice the tail of one run of ins to the
;; usually expensive on modern machines, and can be extremely expensive on ;; beginning of the next.
;; modern Schemes (e.g., ones that have generational GC's). #;
;; It just zips down contiguous runs of in and out elts in LIS doing the (define (filter! pred lis)
;; minimal number of SET-CDR!s to splice the tail of one run of ins to the
;; beginning of the next.
#;
(define (filter! pred lis)
(check-arg procedure? pred 'filter!) (check-arg procedure? pred 'filter!)
(let lp ((ans lis)) (let lp ((ans lis))
(cond ((null-list? ans) ans) ; Scan looking for (cond ((null-list? ans) ans) ; Scan looking for
((not (pred (car ans))) (lp (cdr ans))) ; first cons of result. ((not (pred (car ans))) (lp (cdr ans))) ; first cons of result.
;; ANS is the eventual answer. ;; ANS is the eventual answer.
;; SCAN-IN: (CDR PREV) = LIS and (CAR PREV) satisfies PRED. ;; SCAN-IN: (CDR PREV) = LIS and (CAR PREV) satisfies PRED.
;; Scan over a contiguous segment of the list that ;; Scan over a contiguous segment of the list that
@ -114,11 +107,9 @@
(scan-in ans (cdr ans)) (scan-in ans (cdr ans))
ans))))) ans)))))
;; Answers share common tail with LIS where possible;
;; the technique is slightly subtle.
;; Answers share common tail with LIS where possible; (define (partition pred lis)
;; the technique is slightly subtle.
(define (partition pred lis)
(check-arg procedure? pred 'partition) (check-arg procedure? pred 'partition)
(let recur ((lis lis)) (let recur ((lis lis))
(if (null-list? lis) (values lis lis) ; Use NOT-PAIR? to handle dotted lists. (if (null-list? lis) (values lis lis) ; Use NOT-PAIR? to handle dotted lists.
@ -129,21 +120,18 @@
(values (if (pair? out) (cons elt in) lis) out) (values (if (pair? out) (cons elt in) lis) out)
(values in (if (pair? in) (cons elt out) lis)))))))) (values in (if (pair? in) (cons elt out) lis))))))))
;; This implementation of PARTITION!
;; - doesn't cons, and uses no stack;
;; This implementation of PARTITION! ;; - is careful not to do redundant SET-CDR! writes, as writes to memory are
;; - doesn't cons, and uses no stack; ;; usually expensive on modern machines, and can be extremely expensive on
;; - is careful not to do redundant SET-CDR! writes, as writes to memory are ;; modern Schemes (e.g., ones that have generational GC's).
;; usually expensive on modern machines, and can be extremely expensive on ;; It just zips down contiguous runs of in and out elts in LIS doing the
;; modern Schemes (e.g., ones that have generational GC's). ;; minimal number of SET-CDR!s to splice these runs together into the result
;; It just zips down contiguous runs of in and out elts in LIS doing the ;; lists.
;; minimal number of SET-CDR!s to splice these runs together into the result #;
;; lists. (define (partition! pred lis)
#;
(define (partition! pred lis)
(check-arg procedure? pred 'partition!) (check-arg procedure? pred 'partition!)
(if (null-list? lis) (values lis lis) (if (null-list? lis) (values lis lis)
;; This pair of loops zips down contiguous in & out runs of the ;; This pair of loops zips down contiguous in & out runs of the
;; list, splicing the runs together. The invariants are ;; list, splicing the runs together. The invariants are
;; SCAN-IN: (cdr in-prev) = LIS. ;; SCAN-IN: (cdr in-prev) = LIS.
@ -156,7 +144,6 @@
(begin (set-cdr! out-prev lis) (begin (set-cdr! out-prev lis)
(scan-out in-prev lis (cdr lis)))) (scan-out in-prev lis (cdr lis))))
(set-cdr! out-prev lis))))) ; Done. (set-cdr! out-prev lis))))) ; Done.
(scan-out (lambda (in-prev out-prev lis) (scan-out (lambda (in-prev out-prev lis)
(let lp ((out-prev out-prev) (lis lis)) (let lp ((out-prev out-prev) (lis lis))
(if (pair? lis) (if (pair? lis)
@ -165,7 +152,6 @@
(scan-in lis out-prev (cdr lis))) (scan-in lis out-prev (cdr lis)))
(lp lis (cdr lis))) (lp lis (cdr lis)))
(set-cdr! in-prev lis)))))) ; Done. (set-cdr! in-prev lis)))))) ; Done.
;; Crank up the scan&splice loops. ;; Crank up the scan&splice loops.
(if (pred (car lis)) (if (pred (car lis))
;; LIS begins in-list. Search for out-list's first pair. ;; LIS begins in-list. Search for out-list's first pair.
@ -174,7 +160,6 @@
((pred (car l)) (lp l (cdr l))) ((pred (car l)) (lp l (cdr l)))
(else (scan-out prev-l l (cdr l)) (else (scan-out prev-l l (cdr l))
(values lis l)))) ; Done. (values lis l)))) ; Done.
;; LIS begins out-list. Search for in-list's first pair. ;; LIS begins out-list. Search for in-list's first pair.
(let lp ((prev-l lis) (l (cdr lis))) (let lp ((prev-l lis) (l (cdr lis)))
(cond ((not (pair? l)) (values l lis)) (cond ((not (pair? l)) (values l lis))
@ -183,11 +168,9 @@
(values l lis)) ; Done. (values l lis)) ; Done.
(else (lp l (cdr l))))))))) (else (lp l (cdr l)))))))))
;; Inline us, please.
(define (remove pred l) (filter (lambda (x) (not (pred x))) l))
#;
(define (remove! pred l) (filter! (lambda (x) (not (pred x))) l))
;; Inline us, please.
(define (remove pred l) (filter (lambda (x) (not (pred x))) l))
#;
(define (remove! pred l) (filter! (lambda (x) (not (pred x))) l))
)
;;; filter.ss ends here ;;; filter.ss ends here

100
collects/srfi/1/fold.ss
View File

@ -32,16 +32,15 @@
;; hold me liable for its use. Please send bug reports to shivers@ai.mit.edu. ;; hold me liable for its use. Please send bug reports to shivers@ai.mit.edu.
;; -Olin ;; -Olin
(module fold #lang mzscheme
mzscheme
(require srfi/optional (require srfi/optional
"predicate.ss" "predicate.ss"
"selector.ss" "selector.ss"
"util.ss") "util.ss"
(require srfi/8/receive) srfi/8/receive)
(provide (rename my-map map) (provide (rename my-map map)
(rename my-for-each for-each) (rename my-for-each for-each)
fold fold
unfold unfold
@ -58,11 +57,10 @@
filter-map filter-map
map-in-order) map-in-order)
;; fold/unfold
;;;;;;;;;;;;;;
;; fold/unfold (define (unfold-right p f g seed . maybe-tail)
;;;;;;;;;;;;;;
(define (unfold-right p f g seed . maybe-tail)
(check-arg procedure? p 'unfold-right) (check-arg procedure? p 'unfold-right)
(check-arg procedure? f 'unfold-right) (check-arg procedure? f 'unfold-right)
(check-arg procedure? g 'unfold-right) (check-arg procedure? g 'unfold-right)
@ -71,40 +69,33 @@
(lp (g seed) (lp (g seed)
(cons (f seed) ans))))) (cons (f seed) ans)))))
(define (unfold p f g seed . maybe-tail-gen)
(define (unfold p f g seed . maybe-tail-gen)
(check-arg procedure? p 'unfold) (check-arg procedure? p 'unfold)
(check-arg procedure? f 'unfold) (check-arg procedure? f 'unfold)
(check-arg procedure? g 'unfold) (check-arg procedure? g 'unfold)
(if (pair? maybe-tail-gen) (if (pair? maybe-tail-gen)
(let ((tail-gen (car maybe-tail-gen))) (let ((tail-gen (car maybe-tail-gen)))
(if (pair? (cdr maybe-tail-gen)) (if (pair? (cdr maybe-tail-gen))
(apply error "Too many arguments" unfold p f g seed maybe-tail-gen) (apply error "Too many arguments" unfold p f g seed maybe-tail-gen)
(let recur ((seed seed)) (let recur ((seed seed))
(if (p seed) (tail-gen seed) (if (p seed) (tail-gen seed)
(cons (f seed) (recur (g seed))))))) (cons (f seed) (recur (g seed)))))))
(let recur ((seed seed)) (let recur ((seed seed))
(if (p seed) '() (if (p seed) '()
(cons (f seed) (recur (g seed))))))) (cons (f seed) (recur (g seed)))))))
(define (fold kons knil lis1 . lists)
(define (fold kons knil lis1 . lists)
(check-arg procedure? kons 'fold) (check-arg procedure? kons 'fold)
(if (pair? lists) (if (pair? lists)
(let lp ((lists (cons lis1 lists)) (ans knil)) ; N-ary case (let lp ((lists (cons lis1 lists)) (ans knil)) ; N-ary case
(receive (cars+ans cdrs) (%cars+cdrs+ lists ans) (receive (cars+ans cdrs) (%cars+cdrs+ lists ans)
(if (null? cars+ans) ans ; Done. (if (null? cars+ans) ans ; Done.
(lp cdrs (apply kons cars+ans))))) (lp cdrs (apply kons cars+ans)))))
(let lp ((lis lis1) (ans knil)) ; Fast path (let lp ((lis lis1) (ans knil)) ; Fast path
(if (null-list? lis) ans (if (null-list? lis) ans
(lp (cdr lis) (kons (car lis) ans)))))) (lp (cdr lis) (kons (car lis) ans))))))
(define (fold-right kons knil lis1 . lists)
(define (fold-right kons knil lis1 . lists)
(check-arg procedure? kons 'fold-right) (check-arg procedure? kons 'fold-right)
(if (pair? lists) (if (pair? lists)
(let recur ((lists (cons lis1 lists))) ; N-ary case (let recur ((lists (cons lis1 lists))) ; N-ary case
@ -117,41 +108,37 @@
(let ((head (car lis))) (let ((head (car lis)))
(kons head (recur (cdr lis)))))))) (kons head (recur (cdr lis))))))))
(define (pair-fold-right f zero lis1 . lists)
(define (pair-fold-right f zero lis1 . lists)
(check-arg procedure? f 'pair-fold-right) (check-arg procedure? f 'pair-fold-right)
(if (pair? lists) (if (pair? lists)
(let recur ((lists (cons lis1 lists))) ; N-ary case (let recur ((lists (cons lis1 lists))) ; N-ary case
(let ((cdrs (%cdrs lists))) (let ((cdrs (%cdrs lists)))
(if (null? cdrs) zero (if (null? cdrs) zero
(apply f (append lists (list (recur cdrs))))))) (apply f (append lists (list (recur cdrs)))))))
(let recur ((lis lis1)) ; Fast path (let recur ((lis lis1)) ; Fast path
(if (null-list? lis) zero (f lis (recur (cdr lis))))))) (if (null-list? lis) zero (f lis (recur (cdr lis)))))))
(define (pair-fold f zero lis1 . lists) (define (pair-fold f zero lis1 . lists)
(check-arg procedure? f 'pair-fold) (check-arg procedure? f 'pair-fold)
(if (pair? lists) (if (pair? lists)
(let lp ((lists (cons lis1 lists)) (ans zero)) ; N-ary case (let lp ((lists (cons lis1 lists)) (ans zero)) ; N-ary case
(let ((tails (%cdrs lists))) (let ((tails (%cdrs lists)))
(if (null? tails) ans (if (null? tails) ans
(lp tails (apply f (append lists (list ans))))))) (lp tails (apply f (append lists (list ans)))))))
(let lp ((lis lis1) (ans zero)) (let lp ((lis lis1) (ans zero))
(if (null-list? lis) ans (if (null-list? lis) ans
(let ((tail (cdr lis))) ; Grab the cdr now, (let ((tail (cdr lis))) ; Grab the cdr now,
(lp tail (f lis ans))))))) ; in case F SET-CDR!s LIS. (lp tail (f lis ans))))))) ; in case F SET-CDR!s LIS.
;; REDUCE and REDUCE-RIGHT only use RIDENTITY in the empty-list case.
;; These cannot meaningfully be n-ary.
;; REDUCE and REDUCE-RIGHT only use RIDENTITY in the empty-list case. (define (reduce f ridentity lis)
;; These cannot meaningfully be n-ary.
(define (reduce f ridentity lis)
(check-arg procedure? f 'reduce) (check-arg procedure? f 'reduce)
(if (null-list? lis) ridentity (if (null-list? lis) ridentity
(fold f (car lis) (cdr lis)))) (fold f (car lis) (cdr lis))))
(define (reduce-right f ridentity lis) (define (reduce-right f ridentity lis)
(check-arg procedure? f 'reduce-right) (check-arg procedure? f 'reduce-right)
(if (null-list? lis) ridentity (if (null-list? lis) ridentity
(let recur ((head (car lis)) (lis (cdr lis))) (let recur ((head (car lis)) (lis (cdr lis)))
@ -159,18 +146,16 @@
(f head (recur (car lis) (cdr lis))) (f head (recur (car lis) (cdr lis)))
head)))) head))))
;; Mappers: append-map append-map! pair-for-each map! filter-map map-in-order
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define (append-map f lis1 . lists)
;; Mappers: append-map append-map! pair-for-each map! filter-map map-in-order
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define (append-map f lis1 . lists)
(really-append-map append-map append f lis1 lists)) (really-append-map append-map append f lis1 lists))
#; #;
(define (append-map! f lis1 . lists) (define (append-map! f lis1 . lists)
(really-append-map append-map! append! f lis1 lists)) (really-append-map append-map! append! f lis1 lists))
(define (really-append-map who appender f lis1 lists) (define (really-append-map who appender f lis1 lists)
(check-arg procedure? f 'who) (check-arg procedure? f 'who)
(if (pair? lists) (if (pair? lists)
(receive (cars cdrs) (%cars+cdrs (cons lis1 lists)) (receive (cars cdrs) (%cars+cdrs (cons lis1 lists))
@ -180,7 +165,6 @@
(receive (cars2 cdrs2) (%cars+cdrs cdrs) (receive (cars2 cdrs2) (%cars+cdrs cdrs)
(if (null? cars2) vals (if (null? cars2) vals
(appender vals (recur cars2 cdrs2)))))))) (appender vals (recur cars2 cdrs2))))))))
;; Fast path ;; Fast path
(if (null-list? lis1) '() (if (null-list? lis1) '()
(let recur ((elt (car lis1)) (rest (cdr lis1))) (let recur ((elt (car lis1)) (rest (cdr lis1)))
@ -188,17 +172,14 @@
(if (null-list? rest) vals (if (null-list? rest) vals
(appender vals (recur (car rest) (cdr rest))))))))) (appender vals (recur (car rest) (cdr rest)))))))))
(define (pair-for-each proc lis1 . lists)
(define (pair-for-each proc lis1 . lists)
(check-arg procedure? proc 'pair-for-each) (check-arg procedure? proc 'pair-for-each)
(if (pair? lists) (if (pair? lists)
(let lp ((lists (cons lis1 lists))) (let lp ((lists (cons lis1 lists)))
(let ((tails (%cdrs lists))) (let ((tails (%cdrs lists)))
(if (pair? tails) (if (pair? tails)
(begin (apply proc lists) (begin (apply proc lists)
(lp tails))))) (lp tails)))))
;; Fast path. ;; Fast path.
(let lp ((lis lis1)) (let lp ((lis lis1))
(if (not (null-list? lis)) (if (not (null-list? lis))
@ -206,9 +187,9 @@
(proc lis) ; in case PROC SET-CDR!s LIS. (proc lis) ; in case PROC SET-CDR!s LIS.
(lp tail)))))) (lp tail))))))
;; We stop when LIS1 runs out, not when any list runs out. ;; We stop when LIS1 runs out, not when any list runs out.
#; #;
(define (map! f lis1 . lists) (define (map! f lis1 . lists)
(check-arg procedure? f 'map!) (check-arg procedure? f 'map!)
(if (pair? lists) (if (pair? lists)
(let lp ((lis1 lis1) (lists lists)) (let lp ((lis1 lis1) (lists lists))
@ -216,14 +197,12 @@
(receive (heads tails) (%cars+cdrs/no-test lists) (receive (heads tails) (%cars+cdrs/no-test lists)
(set-car! lis1 (apply f (car lis1) heads)) (set-car! lis1 (apply f (car lis1) heads))
(lp (cdr lis1) tails)))) (lp (cdr lis1) tails))))
;; Fast path. ;; Fast path.
(pair-for-each (lambda (pair) (set-car! pair (f (car pair)))) lis1)) (pair-for-each (lambda (pair) (set-car! pair (f (car pair)))) lis1))
lis1) lis1)
;; Map F across L, and save up all the non-false results.
;; Map F across L, and save up all the non-false results. (define (filter-map f lis1 . lists)
(define (filter-map f lis1 . lists)
(check-arg procedure? f 'filter-map) (check-arg procedure? f 'filter-map)
(if (pair? lists) (if (pair? lists)
(let recur ((lists (cons lis1 lists))) (let recur ((lists (cons lis1 lists)))
@ -232,7 +211,6 @@
(cond ((apply f cars) => (lambda (x) (cons x (recur cdrs)))) (cond ((apply f cars) => (lambda (x) (cons x (recur cdrs))))
(else (recur cdrs))) ; Tail call in this arm. (else (recur cdrs))) ; Tail call in this arm.
'()))) '())))
;; Fast path. ;; Fast path.
(let recur ((lis lis1)) (let recur ((lis lis1))
(if (null-list? lis) lis (if (null-list? lis) lis
@ -240,12 +218,11 @@
(cond ((f (car lis)) => (lambda (x) (cons x tail))) (cond ((f (car lis)) => (lambda (x) (cons x tail)))
(else tail))))))) (else tail)))))))
;; Map F across lists, guaranteeing to go left-to-right.
;; NOTE: Some implementations of R5RS MAP are compliant with this spec;
;; in which case this procedure may simply be defined as a synonym for MAP.
;; Map F across lists, guaranteeing to go left-to-right. (define (map-in-order f lis1 . lists)
;; NOTE: Some implementations of R5RS MAP are compliant with this spec;
;; in which case this procedure may simply be defined as a synonym for MAP.
(define (map-in-order f lis1 . lists)
(check-arg procedure? f 'map-in-order) (check-arg procedure? f 'map-in-order)
(if (pair? lists) (if (pair? lists)
(let recur ((lists (cons lis1 lists))) (let recur ((lists (cons lis1 lists)))
@ -254,7 +231,6 @@
(let ((x (apply f cars))) ; Do head first, (let ((x (apply f cars))) ; Do head first,
(cons x (recur cdrs))) ; then tail. (cons x (recur cdrs))) ; then tail.
'()))) '())))
;; Fast path. ;; Fast path.
(let recur ((lis lis1)) (let recur ((lis lis1))
(if (null-list? lis) lis (if (null-list? lis) lis
@ -262,16 +238,15 @@
(x (f (car lis)))) ; Do head first, (x (f (car lis)))) ; Do head first,
(cons x (recur tail))))))) ; then tail. (cons x (recur tail))))))) ; then tail.
;; We extend MAP to handle arguments of unequal length.
;; We extend MAP to handle arguments of unequal length. (define my-map map-in-order)
(define my-map map-in-order)
;;; Apply F across lists, guaranteeing to go left-to-right. ;;; Apply F across lists, guaranteeing to go left-to-right.
;;; NOTE: Some implementations of R5RS MAP are compliant with this spec; ;;; NOTE: Some implementations of R5RS MAP are compliant with this spec;
;;; in which case this procedure may simply be defined as a synonym for FOR-EACH. ;;; in which case this procedure may simply be defined as a synonym for FOR-EACH.
(define (my-for-each f lis1 . lists) (define (my-for-each f lis1 . lists)
(check-arg procedure? f for-each) (check-arg procedure? f for-each)
(if (pair? lists) (if (pair? lists)
(let recur ((lists (cons lis1 lists))) (let recur ((lists (cons lis1 lists)))
@ -280,12 +255,11 @@
(begin (begin
(apply f cars) ; Do head first, (apply f cars) ; Do head first,
(recur cdrs))))) ; then tail. (recur cdrs))))) ; then tail.
;; Fast path. ;; Fast path.
(let recur ((lis lis1)) (let recur ((lis lis1))
(if (not (null-list? lis)) (if (not (null-list? lis))
(begin (begin
(f (car lis)) ; Do head first, (f (car lis)) ; Do head first,
(recur (cdr lis))))))) (recur (cdr lis)))))))
)
;;; fold.ss ends here ;;; fold.ss ends here

15
collects/srfi/1/list.ss
View File

@ -212,11 +212,11 @@
;; with an s: to avoid colliding with mzscheme. The wrapper 1.ss ;; with an s: to avoid colliding with mzscheme. The wrapper 1.ss
;; changes their names back to the non-prefixed form. ;; changes their names back to the non-prefixed form.
(module list mzscheme #lang mzscheme
(require srfi/optional) (require srfi/optional)
(require "cons.ss" (require "cons.ss"
"selector.ss" "selector.ss"
"predicate.ss" "predicate.ss"
"misc.ss" "misc.ss"
@ -231,9 +231,7 @@
(rename "alist.ss" s:assoc assoc) (rename "alist.ss" s:assoc assoc)
"lset.ss") "lset.ss")
(provide (all-from "cons.ss")
(provide
(all-from "cons.ss")
(all-from "selector.ss") (all-from "selector.ss")
(all-from "predicate.ss") (all-from "predicate.ss")
(all-from "misc.ss") (all-from "misc.ss")
@ -243,8 +241,3 @@
(all-from "delete.ss") (all-from "delete.ss")
(all-from "alist.ss") (all-from "alist.ss")
(all-from "lset.ss")) (all-from "lset.ss"))
;;end of the unit
)

88
collects/srfi/1/lset.ss
View File

@ -32,19 +32,18 @@
;; hold me liable for its use. Please send bug reports to shivers@ai.mit.edu. ;; hold me liable for its use. Please send bug reports to shivers@ai.mit.edu.
;; -Olin ;; -Olin
(module lset #lang mzscheme
mzscheme
(require srfi/optional (require srfi/optional
(all-except "search.ss" member) (all-except "search.ss" member)
(all-except "fold.ss" map for-each) (all-except "fold.ss" map for-each)
(rename "search.ss" s:member member) (rename "search.ss" s:member member)
"delete.ss" "delete.ss"
"predicate.ss" "predicate.ss"
"filter.ss") "filter.ss"
(require srfi/8/receive) srfi/8/receive)
(provide lset<= (provide lset<=
lset= lset=
lset-adjoin lset-adjoin
lset-union lset-union
@ -57,22 +56,22 @@
lset-diff+intersection lset-diff+intersection
(rename lset-diff+intersection lset-diff+intersection!)) (rename lset-diff+intersection lset-diff+intersection!))
;; Lists-as-sets ;; Lists-as-sets
;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;
;; This is carefully tuned code; do not modify casually. ;; This is carefully tuned code; do not modify casually.
;; - It is careful to share storage when possible; ;; - It is careful to share storage when possible;
;; - Side-effecting code tries not to perform redundant writes. ;; - Side-effecting code tries not to perform redundant writes.
;; - It tries to avoid linear-time scans in special cases where constant-time ;; - It tries to avoid linear-time scans in special cases where constant-time
;; computations can be performed. ;; computations can be performed.
;; - It relies on similar properties from the other list-lib procs it calls. ;; - It relies on similar properties from the other list-lib procs it calls.
;; For example, it uses the fact that the implementations of MEMBER and ;; For example, it uses the fact that the implementations of MEMBER and
;; FILTER in this source code share longest common tails between args ;; FILTER in this source code share longest common tails between args
;; and results to get structure sharing in the lset procedures. ;; and results to get structure sharing in the lset procedures.
(define (%lset2<= = lis1 lis2) (every (lambda (x) (s:member x lis2 =)) lis1)) (define (%lset2<= = lis1 lis2) (every (lambda (x) (s:member x lis2 =)) lis1))
(define (lset<= = . lists) (define (lset<= = . lists)
(check-arg procedure? = 'lset<=) (check-arg procedure? = 'lset<=)
(or (not (pair? lists)) ; 0-ary case (or (not (pair? lists)) ; 0-ary case
(let lp ((s1 (car lists)) (rest (cdr lists))) (let lp ((s1 (car lists)) (rest (cdr lists)))
@ -82,7 +81,7 @@
(%lset2<= = s1 s2)) ; Real test (%lset2<= = s1 s2)) ; Real test
(lp s2 rest))))))) (lp s2 rest)))))))
(define (lset= = . lists) (define (lset= = . lists)
(check-arg procedure? = 'lset=) (check-arg procedure? = 'lset=)
(or (not (pair? lists)) ; 0-ary case (or (not (pair? lists)) ; 0-ary case
(let lp ((s1 (car lists)) (rest (cdr lists))) (let lp ((s1 (car lists)) (rest (cdr lists)))
@ -93,28 +92,27 @@
(and (%lset2<= = s1 s2) (%lset2<= = s2 s1))) ; Real test (and (%lset2<= = s1 s2) (%lset2<= = s2 s1))) ; Real test
(lp s2 rest))))))) (lp s2 rest)))))))
(define (lset-adjoin = lis . elts)
(define (lset-adjoin = lis . elts)
(check-arg procedure? = 'lset-adjoin) (check-arg procedure? = 'lset-adjoin)
(fold (lambda (elt ans) (if (s:member elt ans =) ans (cons elt ans))) (fold (lambda (elt ans) (if (s:member elt ans =) ans (cons elt ans)))
lis elts)) lis elts))
(define (lset-union = . lists)
(define (lset-union = . lists)
(check-arg procedure? = 'lset-union) (check-arg procedure? = 'lset-union)
(reduce (lambda (lis ans) ; Compute ANS + LIS. (reduce (lambda (lis ans) ; Compute ANS + LIS.
(cond ((null? lis) ans) ; Don't copy any lists (cond ((null? lis) ans) ; Don't copy any lists
((null? ans) lis) ; if we don't have to. ((null? ans) lis) ; if we don't have to.
((eq? lis ans) ans) ((eq? lis ans) ans)
(else (else
(fold (lambda (elt ans) (if (any (lambda (x) (= x elt)) ans) (fold (lambda (elt ans)
(if (any (lambda (x) (= x elt)) ans)
ans ans
(cons elt ans))) (cons elt ans)))
ans lis)))) ans lis))))
'() lists)) '() lists))
#; #;
(define (lset-union! = . lists) (define (lset-union! = . lists)
(check-arg procedure? = 'lset-union!) (check-arg procedure? = 'lset-union!)
(reduce (lambda (lis ans) ; Splice new elts of LIS onto the front of ANS. (reduce (lambda (lis ans) ; Splice new elts of LIS onto the front of ANS.
(cond ((null? lis) ans) ; Don't copy any lists (cond ((null? lis) ans) ; Don't copy any lists
@ -129,8 +127,7 @@
ans lis)))) ans lis))))
'() lists)) '() lists))
(define (lset-intersection = lis1 . lists)
(define (lset-intersection = lis1 . lists)
(check-arg procedure? = 'lset-intersection) (check-arg procedure? = 'lset-intersection)
(let ((lists (delete lis1 lists eq?))) ; Throw out any LIS1 vals. (let ((lists (delete lis1 lists eq?))) ; Throw out any LIS1 vals.
(cond ((any null-list? lists) '()) ; Short cut (cond ((any null-list? lists) '()) ; Short cut
@ -139,8 +136,8 @@
(every (lambda (lis) (s:member x lis =)) lists)) (every (lambda (lis) (s:member x lis =)) lists))
lis1))))) lis1)))))
#; #;
(define (lset-intersection! = lis1 . lists) (define (lset-intersection! = lis1 . lists)
(check-arg procedure? = 'lset-intersection!) (check-arg procedure? = 'lset-intersection!)
(let ((lists (delete lis1 lists eq?))) ; Throw out any LIS1 vals. (let ((lists (delete lis1 lists eq?))) ; Throw out any LIS1 vals.
(cond ((any null-list? lists) '()) ; Short cut (cond ((any null-list? lists) '()) ; Short cut
@ -149,8 +146,7 @@
(every (lambda (lis) (s:member x lis =)) lists)) (every (lambda (lis) (s:member x lis =)) lists))
lis1))))) lis1)))))
(define (lset-difference = lis1 . lists)
(define (lset-difference = lis1 . lists)
(check-arg procedure? = 'lset-difference) (check-arg procedure? = 'lset-difference)
(let ((lists (filter pair? lists))) ; Throw out empty lists. (let ((lists (filter pair? lists))) ; Throw out empty lists.
(cond ((null? lists) lis1) ; Short cut (cond ((null? lists) lis1) ; Short cut
@ -160,8 +156,8 @@
lists)) lists))
lis1))))) lis1)))))
#; #;
(define (lset-difference! = lis1 . lists) (define (lset-difference! = lis1 . lists)
(check-arg procedure? = 'lset-difference!) (check-arg procedure? = 'lset-difference!)
(let ((lists (filter pair? lists))) ; Throw out empty lists. (let ((lists (filter pair? lists))) ; Throw out empty lists.
(cond ((null? lists) lis1) ; Short cut (cond ((null? lists) lis1) ; Short cut
@ -171,8 +167,7 @@
lists)) lists))
lis1))))) lis1)))))
(define (lset-xor = . lists)
(define (lset-xor = . lists)
(check-arg procedure? = 'lset-xor) (check-arg procedure? = 'lset-xor)
(reduce (lambda (b a) ; Compute A xor B: (reduce (lambda (b a) ; Compute A xor B:
;; Note that this code relies on the constant-time ;; Note that this code relies on the constant-time
@ -181,7 +176,6 @@
;; cuts for the cases A = (), B = (), and A eq? B. It takes ;; cuts for the cases A = (), B = (), and A eq? B. It takes
;; a careful case analysis to see it, but it's carefully ;; a careful case analysis to see it, but it's carefully
;; built in. ;; built in.
;; Compute a-b and a^b, then compute b-(a^b) and ;; Compute a-b and a^b, then compute b-(a^b) and
;; cons it onto the front of a-b. ;; cons it onto the front of a-b.
(receive (a-b a-int-b) (lset-diff+intersection = a b) (receive (a-b a-int-b) (lset-diff+intersection = a b)
@ -193,8 +187,8 @@
b))))) b)))))
'() lists)) '() lists))
#; #;
(define (lset-xor! = . lists) (define (lset-xor! = . lists)
(check-arg procedure? = 'lset-xor!) (check-arg procedure? = 'lset-xor!)
(reduce (lambda (b a) ; Compute A xor B: (reduce (lambda (b a) ; Compute A xor B:
;; Note that this code relies on the constant-time ;; Note that this code relies on the constant-time
@ -203,21 +197,20 @@
;; cuts for the cases A = (), B = (), and A eq? B. It takes ;; cuts for the cases A = (), B = (), and A eq? B. It takes
;; a careful case analysis to see it, but it's carefully ;; a careful case analysis to see it, but it's carefully
;; built in. ;; built in.
;; Compute a-b and a^b, then compute b-(a^b) and ;; Compute a-b and a^b, then compute b-(a^b) and
;; cons it onto the front of a-b. ;; cons it onto the front of a-b.
(receive (a-b a-int-b) (lset-diff+intersection! = a b) (receive (a-b a-int-b) (lset-diff+intersection! = a b)
(cond ((null? a-b) (lset-difference! = b a)) (cond ((null? a-b) (lset-difference! = b a))
((null? a-int-b) (append! b a)) ((null? a-int-b) (append! b a))
(else (pair-fold (lambda (b-pair ans) (else (pair-fold
(lambda (b-pair ans)
(if (s:member (car b-pair) a-int-b =) ans (if (s:member (car b-pair) a-int-b =) ans
(begin (set-cdr! b-pair ans) b-pair))) (begin (set-cdr! b-pair ans) b-pair)))
a-b a-b
b))))) b)))))
'() lists)) '() lists))
(define (lset-diff+intersection = lis1 . lists)
(define (lset-diff+intersection = lis1 . lists)
(check-arg procedure? = 'lset-diff+intersection) (check-arg procedure? = 'lset-diff+intersection)
(cond ((every null-list? lists) (values lis1 '())) ; Short cut (cond ((every null-list? lists) (values lis1 '())) ; Short cut
((memq lis1 lists) (values '() lis1)) ; Short cut ((memq lis1 lists) (values '() lis1)) ; Short cut
@ -226,8 +219,8 @@
lists))) lists)))
lis1)))) lis1))))
#; #;
(define (lset-diff+intersection! = lis1 . lists) (define (lset-diff+intersection! = lis1 . lists)
(check-arg procedure? = 'lset-diff+intersection!) (check-arg procedure? = 'lset-diff+intersection!)
(cond ((every null-list? lists) (values lis1 '())) ; Short cut (cond ((every null-list? lists) (values lis1 '())) ; Short cut
((memq lis1 lists) (values '() lis1)) ; Short cut ((memq lis1 lists) (values '() lis1)) ; Short cut
@ -236,7 +229,4 @@
lists))) lists)))
lis1)))) lis1))))
)
;;; lset.ss ends here ;;; lset.ss ends here

82
collects/srfi/1/misc.ss
View File

@ -32,18 +32,17 @@
;; hold me liable for its use. Please send bug reports to shivers@ai.mit.edu. ;; hold me liable for its use. Please send bug reports to shivers@ai.mit.edu.
;; -Olin ;; -Olin
(module misc #lang mzscheme
mzscheme
(require srfi/optional (require srfi/optional
"predicate.ss" "predicate.ss"
"selector.ss" "selector.ss"
"util.ss" "util.ss"
(only "fold.ss" reduce-right) (only "fold.ss" reduce-right)
(rename "fold.ss" srfi-1:map map)) (rename "fold.ss" srfi-1:map map)
(require srfi/8/receive) srfi/8/receive)
(provide length+ (provide length+
concatenate concatenate
(rename append append!) (rename append append!)
(rename concatenate concatenate!) (rename concatenate concatenate!)
@ -58,13 +57,11 @@
unzip5 unzip5
count) count)
;; count
;; count ;;;;;;;;
;;;;;;;; (define (count pred list1 . lists)
(define (count pred list1 . lists)
(check-arg procedure? pred 'count) (check-arg procedure? pred 'count)
(if (pair? lists) (if (pair? lists)
;; N-ary case ;; N-ary case
(let lp ((list1 list1) (lists lists) (i 0)) (let lp ((list1 list1) (lists lists) (i 0))
(if (null-list? list1) i (if (null-list? list1) i
@ -72,14 +69,12 @@
(if (null? as) i (if (null? as) i
(lp (cdr list1) ds (lp (cdr list1) ds
(if (apply pred (car list1) as) (+ i 1) i)))))) (if (apply pred (car list1) as) (+ i 1) i))))))
;; Fast path ;; Fast path
(let lp ((lis list1) (i 0)) (let lp ((lis list1) (i 0))
(if (null-list? lis) i (if (null-list? lis) i
(lp (cdr lis) (if (pred (car lis)) (+ i 1) i)))))) (lp (cdr lis) (if (pred (car lis)) (+ i 1) i))))))
(define (length+ x) ; Returns #f if X is circular.
(define (length+ x) ; Returns #f if X is circular.
(let lp ((x x) (lag x) (len 0)) (let lp ((x x) (lag x) (len 0))
(if (pair? x) (if (pair? x)
(let ((x (cdr x)) (let ((x (cdr x))
@ -92,16 +87,14 @@
len)) len))
len))) len)))
(define (zip list1 . more-lists) (apply srfi-1:map list list1 more-lists))
;; Unzippers -- 1 through 5
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define (zip list1 . more-lists) (apply srfi-1:map list list1 more-lists)) (define (unzip1 lis) (map car lis))
;; Unzippers -- 1 through 5 (define (unzip2 lis)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define (unzip1 lis) (map car lis))
(define (unzip2 lis)
(let recur ((lis lis)) (let recur ((lis lis))
(if (null-list? lis) (values lis lis) ; Use NOT-PAIR? to handle (if (null-list? lis) (values lis lis) ; Use NOT-PAIR? to handle
(let ((elt (car lis))) ; dotted lists. (let ((elt (car lis))) ; dotted lists.
@ -109,7 +102,7 @@
(values (cons (car elt) a) (values (cons (car elt) a)
(cons (cadr elt) b))))))) (cons (cadr elt) b)))))))
(define (unzip3 lis) (define (unzip3 lis)
(let recur ((lis lis)) (let recur ((lis lis))
(if (null-list? lis) (values lis lis lis) (if (null-list? lis) (values lis lis lis)
(let ((elt (car lis))) (let ((elt (car lis)))
@ -118,7 +111,7 @@
(cons (cadr elt) b) (cons (cadr elt) b)
(cons (caddr elt) c))))))) (cons (caddr elt) c)))))))
(define (unzip4 lis) (define (unzip4 lis)
(let recur ((lis lis)) (let recur ((lis lis))
(if (null-list? lis) (values lis lis lis lis) (if (null-list? lis) (values lis lis lis lis)
(let ((elt (car lis))) (let ((elt (car lis)))
@ -128,7 +121,7 @@
(cons (caddr elt) c) (cons (caddr elt) c)
(cons (cadddr elt) d))))))) (cons (cadddr elt) d)))))))
(define (unzip5 lis) (define (unzip5 lis)
(let recur ((lis lis)) (let recur ((lis lis))
(if (null-list? lis) (values lis lis lis lis lis) (if (null-list? lis) (values lis lis lis lis lis)
(let ((elt (car lis))) (let ((elt (car lis)))
@ -139,19 +132,18 @@
(cons (cadddr elt) d) (cons (cadddr elt) d)
(cons (car (cddddr elt)) e))))))) (cons (car (cddddr elt)) e)))))))
;; append! append-reverse append-reverse! concatenate concatenate!
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; append! append-reverse append-reverse! concatenate concatenate! #;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; (define (my-append! . lists)
#;
(define (my-append! . lists)
;; First, scan through lists looking for a non-empty one. ;; First, scan through lists looking for a non-empty one.
(let lp ((lists lists) (prev '())) (let lp ((lists lists) (prev '()))
(if (not (pair? lists)) prev (if (not (pair? lists)) prev
(let ((first (car lists)) (let ((first (car lists))
(rest (cdr lists))) (rest (cdr lists)))
(if (not (pair? first)) (lp rest first) (if (not (pair? first)) (lp rest first)
; ;; Now, do the splicing. ;; Now, do the splicing.
(let lp2 ((tail-cons (last-pair first)) (let lp2 ((tail-cons (last-pair first))
(rest rest)) (rest rest))
(if (pair? rest) (if (pair? rest)
@ -163,40 +155,38 @@
first))))))) first)))))))
;;(define (append-reverse rev-head tail) (fold cons tail rev-head)) ;;(define (append-reverse rev-head tail) (fold cons tail rev-head))
;;(define (append-reverse! rev-head tail) ;;(define (append-reverse! rev-head tail)
;; (pair-fold (lambda (pair tail) (set-cdr! pair tail) pair) ;; (pair-fold (lambda (pair tail) (set-cdr! pair tail) pair)
;; tail ;; tail
;; rev-head)) ;; rev-head))
;; Hand-inline the FOLD and PAIR-FOLD ops for speed. ;; Hand-inline the FOLD and PAIR-FOLD ops for speed.
(define (append-reverse rev-head tail) (define (append-reverse rev-head tail)
(let lp ((rev-head rev-head) (tail tail)) (let lp ((rev-head rev-head) (tail tail))
(if (null-list? rev-head) tail (if (null-list? rev-head) tail
(lp (cdr rev-head) (cons (car rev-head) tail))))) (lp (cdr rev-head) (cons (car rev-head) tail)))))
#; #;
(define (append-reverse! rev-head tail) (define (append-reverse! rev-head tail)
(let lp ((rev-head rev-head) (tail tail)) (let lp ((rev-head rev-head) (tail tail))
(if (null-list? rev-head) tail (if (null-list? rev-head) tail
(let ((next-rev (cdr rev-head))) (let ((next-rev (cdr rev-head)))
(set-cdr! rev-head tail) (set-cdr! rev-head tail)
(lp next-rev rev-head))))) (lp next-rev rev-head)))))
(define (concatenate lists) (reduce-right append '() lists))
#;
(define (concatenate! lists) (reduce-right my-append! '() lists))
(define (concatenate lists) (reduce-right append '() lists)) #;
#; (define (my-reverse! lis)
(define (concatenate! lists) (reduce-right my-append! '() lists))
#;
(define (my-reverse! lis)
(let lp ((lis lis) (ans '())) (let lp ((lis lis) (ans '()))
(if (null-list? lis) ans (if (null-list? lis) ans
(let ((tail (cdr lis))) (let ((tail (cdr lis)))
(set-cdr! lis ans) (set-cdr! lis ans)
(lp tail lis))))) (lp tail lis)))))
)
;;; misc.ss ends here ;;; misc.ss ends here

49
collects/srfi/1/predicate.ss
View File

@ -33,12 +33,11 @@
;; -Olin ;; -Olin
(module predicate #lang mzscheme
mzscheme
(require srfi/optional) (require srfi/optional)
(provide pair? (provide pair?
null? null?
proper-list? proper-list?
circular-list? circular-list?
@ -47,12 +46,12 @@
null-list? null-list?
list=) list=)
;; <proper-list> ::= () ; Empty proper list ;; <proper-list> ::= () ; Empty proper list
;; | (cons <x> <proper-list>) ; Proper-list pair ;; | (cons <x> <proper-list>) ; Proper-list pair
;; Note that this definition rules out circular lists -- and this ;; Note that this definition rules out circular lists -- and this
;; function is required to detect this case and return false. ;; function is required to detect this case and return false.
(define (proper-list? x) (define (proper-list? x)
(let lp ((x x) (lag x)) (let lp ((x x) (lag x))
(if (pair? x) (if (pair? x)
(let ((x (cdr x))) (let ((x (cdr x)))
@ -63,15 +62,14 @@
(null? x))) (null? x)))
(null? x)))) (null? x))))
;; A dotted list is a finite list (possibly of length 0) terminated
;; by a non-nil value. Any non-cons, non-nil value (e.g., "foo" or 5)
;; is a dotted list of length 0.
;;
;; <dotted-list> ::= <non-nil,non-pair> ; Empty dotted list
;; | (cons <x> <dotted-list>) ; Proper-list pair
;; A dotted list is a finite list (possibly of length 0) terminated (define (dotted-list? x)
;; by a non-nil value. Any non-cons, non-nil value (e.g., "foo" or 5)
;; is a dotted list of length 0.
;;
;; <dotted-list> ::= <non-nil,non-pair> ; Empty dotted list
;; | (cons <x> <dotted-list>) ; Proper-list pair
(define (dotted-list? x)
(let lp ((x x) (lag x)) (let lp ((x x) (lag x))
(if (pair? x) (if (pair? x)
(let ((x (cdr x))) (let ((x (cdr x)))
@ -82,7 +80,7 @@
(not (null? x)))) (not (null? x))))
(not (null? x))))) (not (null? x)))))
(define (circular-list? x) (define (circular-list? x)
(let lp ((x x) (lag x)) (let lp ((x x) (lag x))
(and (pair? x) (and (pair? x)
(let ((x (cdr x))) (let ((x (cdr x)))
@ -91,18 +89,17 @@
(lag (cdr lag))) (lag (cdr lag)))
(or (eq? x lag) (lp x lag)))))))) (or (eq? x lag) (lp x lag))))))))
(define (not-pair? x) (not (pair? x))) ; Inline me. (define (not-pair? x) (not (pair? x))) ; Inline me.
;; This is a legal definition which is fast and sloppy: ;; This is a legal definition which is fast and sloppy:
;; (define null-list? not-pair?) ;; (define null-list? not-pair?)
;; but we'll provide a more careful one: ;; but we'll provide a more careful one:
(define (null-list? l) (define (null-list? l)
(cond ((pair? l) #f) (cond ((pair? l) #f)
((null? l) #t) ((null? l) #t)
(else (error "null-list?: argument out of domain" l)))) (else (error "null-list?: argument out of domain" l))))
(define (list= = . lists)
(define (list= = . lists)
(or (null? lists) ; special case (or (null? lists) ; special case
(let lp1 ((list-a (car lists)) (others (cdr lists))) (let lp1 ((list-a (car lists)) (others (cdr lists)))
(or (null? others) (or (null? others)
@ -118,6 +115,4 @@
(= (car la) (car lb)) (= (car la) (car lb))
(lp2 (cdr la) (cdr lb))))))))))) (lp2 (cdr la) (cdr lb)))))))))))
)
;;; predicate.ss ends here ;;; predicate.ss ends here

63
collects/srfi/1/search.ss
View File

@ -32,16 +32,15 @@
;; hold me liable for its use. Please send bug reports to shivers@ai.mit.edu. ;; hold me liable for its use. Please send bug reports to shivers@ai.mit.edu.
;; -Olin ;; -Olin
(module search #lang mzscheme
mzscheme
(require mzlib/etc (require mzlib/etc
srfi/optional srfi/optional
"predicate.ss" "predicate.ss"
"util.ss") "util.ss"
(require srfi/8/receive) srfi/8/receive)
(provide (rename my-member member) (provide (rename my-member member)
find find
find-tail find-tail
any any
@ -55,27 +54,27 @@
(rename span span!) (rename span span!)
(rename break break!)) (rename break break!))
;; Extended from R4RS to take an optional comparison argument. ;; Extended from R4RS to take an optional comparison argument.
(define my-member (define my-member
(opt-lambda (x lis (maybe-= equal?)) (opt-lambda (x lis (maybe-= equal?))
(let ((= maybe-=)) (let ((= maybe-=))
(find-tail (lambda (y) (= x y)) lis)))) (find-tail (lambda (y) (= x y)) lis))))
;; find find-tail take-while drop-while span break any every list-index ;; find find-tail take-while drop-while span break any every list-index
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define (find pred list) (define (find pred list)
(cond ((find-tail pred list) => car) (cond ((find-tail pred list) => car)
(else #f))) (else #f)))
(define (find-tail pred list) (define (find-tail pred list)
(check-arg procedure? pred 'find-tail) (check-arg procedure? pred 'find-tail)
(let lp ((list list)) (let lp ((list list))
(and (not (null-list? list)) (and (not (null-list? list))
(if (pred (car list)) list (if (pred (car list)) list
(lp (cdr list)))))) (lp (cdr list))))))
(define (take-while pred lis) (define (take-while pred lis)
(check-arg procedure? pred 'take-while) (check-arg procedure? pred 'take-while)
(let recur ((lis lis)) (let recur ((lis lis))
(if (null-list? lis) '() (if (null-list? lis) '()
@ -84,16 +83,15 @@
(cons x (recur (cdr lis))) (cons x (recur (cdr lis)))
'()))))) '())))))
(define (drop-while pred lis) (define (drop-while pred lis)
(check-arg procedure? pred 'drop-while) (check-arg procedure? pred 'drop-while)
(let lp ((lis lis)) (let lp ((lis lis))
(if (null-list? lis) '() (cond ((null-list? lis) '())
(if (pred (car lis)) ((pred (car lis)) (lp (cdr lis)))
(lp (cdr lis)) (else lis))))
lis))))
#; #;
(define (take-while! pred lis) (define (take-while! pred lis)
(check-arg procedure? pred 'take-while!) (check-arg procedure? pred 'take-while!)
(if (or (null-list? lis) (not (pred (car lis)))) '() (if (or (null-list? lis) (not (pred (car lis)))) '()
(begin (let lp ((prev lis) (rest (cdr lis))) (begin (let lp ((prev lis) (rest (cdr lis)))
@ -103,7 +101,7 @@
(set-cdr! prev '()))))) (set-cdr! prev '())))))
lis))) lis)))
(define (span pred lis) (define (span pred lis)
(check-arg procedure? pred 'span) (check-arg procedure? pred 'span)
(let recur ((lis lis)) (let recur ((lis lis))
(if (null-list? lis) (values '() '()) (if (null-list? lis) (values '() '())
@ -114,7 +112,7 @@
(values '() lis)))))) (values '() lis))))))
#; #;
(define (span! pred lis) (define (span! pred lis)
(check-arg procedure? pred 'span!) (check-arg procedure? pred 'span!)
(if (or (null-list? lis) (not (pred (car lis)))) (values '() lis) (if (or (null-list? lis) (not (pred (car lis)))) (values '() lis)
(let ((suffix (let lp ((prev lis) (rest (cdr lis))) (let ((suffix (let lp ((prev lis) (rest (cdr lis)))
@ -125,15 +123,13 @@
rest))))))) rest)))))))
(values lis suffix)))) (values lis suffix))))
(define (break pred lis) (span (lambda (x) (not (pred x))) lis))
#;
(define (break! pred lis) (span! (lambda (x) (not (pred x))) lis))
(define (break pred lis) (span (lambda (x) (not (pred x))) lis)) (define (any pred lis1 . lists)
#;
(define (break! pred lis) (span! (lambda (x) (not (pred x))) lis))
(define (any pred lis1 . lists)
(check-arg procedure? pred 'any) (check-arg procedure? pred 'any)
(if (pair? lists) (if (pair? lists)
;; N-ary case ;; N-ary case
(receive (heads tails) (%cars+cdrs (cons lis1 lists)) (receive (heads tails) (%cars+cdrs (cons lis1 lists))
(and (pair? heads) (and (pair? heads)
@ -142,7 +138,6 @@
(if (pair? next-heads) (if (pair? next-heads)
(or (apply pred heads) (lp next-heads next-tails)) (or (apply pred heads) (lp next-heads next-tails))
(apply pred heads)))))) ; Last PRED app is tail call. (apply pred heads)))))) ; Last PRED app is tail call.
;; Fast path ;; Fast path
(and (not (null-list? lis1)) (and (not (null-list? lis1))
(let lp ((head (car lis1)) (tail (cdr lis1))) (let lp ((head (car lis1)) (tail (cdr lis1)))
@ -150,17 +145,15 @@
(pred head) ; Last PRED app is tail call. (pred head) ; Last PRED app is tail call.
(or (pred head) (lp (car tail) (cdr tail)))))))) (or (pred head) (lp (car tail) (cdr tail))))))))
;(define (every pred list) ; Simple definition. ;(define (every pred list) ; Simple definition.
; (let lp ((list list)) ; Doesn't return the last PRED value. ; (let lp ((list list)) ; Doesn't return the last PRED value.
; (or (not (pair? list)) ; (or (not (pair? list))
; (and (pred (car list)) ; (and (pred (car list))
; (lp (cdr list)))))) ; (lp (cdr list))))))
(define (every pred lis1 . lists) (define (every pred lis1 . lists)
(check-arg procedure? pred 'every) (check-arg procedure? pred 'every)
(if (pair? lists) (if (pair? lists)
;; N-ary case ;; N-ary case
(receive (heads tails) (%cars+cdrs (cons lis1 lists)) (receive (heads tails) (%cars+cdrs (cons lis1 lists))
(or (not (pair? heads)) (or (not (pair? heads))
@ -169,7 +162,6 @@
(if (pair? next-heads) (if (pair? next-heads)
(and (apply pred heads) (lp next-heads next-tails)) (and (apply pred heads) (lp next-heads next-tails))
(apply pred heads)))))) ; Last PRED app is tail call. (apply pred heads)))))) ; Last PRED app is tail call.
;; Fast path ;; Fast path
(or (null-list? lis1) (or (null-list? lis1)
(let lp ((head (car lis1)) (tail (cdr lis1))) (let lp ((head (car lis1)) (tail (cdr lis1)))
@ -177,21 +169,18 @@
(pred head) ; Last PRED app is tail call. (pred head) ; Last PRED app is tail call.
(and (pred head) (lp (car tail) (cdr tail)))))))) (and (pred head) (lp (car tail) (cdr tail))))))))
(define (list-index pred lis1 . lists) (define (list-index pred lis1 . lists)
(check-arg procedure? pred 'list-index) (check-arg procedure? pred 'list-index)
(if (pair? lists) (if (pair? lists)
;; N-ary case ;; N-ary case
(let lp ((lists (cons lis1 lists)) (n 0)) (let lp ((lists (cons lis1 lists)) (n 0))
(receive (heads tails) (%cars+cdrs lists) (receive (heads tails) (%cars+cdrs lists)
(and (pair? heads) (and (pair? heads)
(if (apply pred heads) n (if (apply pred heads) n
(lp tails (+ n 1)))))) (lp tails (+ n 1))))))
;; Fast path ;; Fast path
(let lp ((lis lis1) (n 0)) (let lp ((lis lis1) (n 0))
(and (not (null-list? lis)) (and (not (null-list? lis))
(if (pred (car lis)) n (lp (cdr lis) (+ n 1))))))) (if (pred (car lis)) n (lp (cdr lis) (+ n 1)))))))
)
;;; search.ss ends here ;;; search.ss ends here

75
collects/srfi/1/selector.ss
View File

@ -32,14 +32,12 @@
;; hold me liable for its use. Please send bug reports to shivers@ai.mit.edu. ;; hold me liable for its use. Please send bug reports to shivers@ai.mit.edu.
;; -Olin ;; -Olin
(module selector #lang mzscheme
mzscheme
(require srfi/optional) (require srfi/optional
(require srfi/8/receive) srfi/8/receive)
(provide (provide first second
first second
third fourth third fourth
fifth sixth fifth sixth
seventh eighth seventh eighth
@ -52,83 +50,81 @@
last last
last-pair) last-pair)
(define first car) (define first car)
(define second cadr) (define second cadr)
(define third caddr) (define third caddr)
(define fourth cadddr) (define fourth cadddr)
(define (fifth x) (car (cddddr x))) (define (fifth x) (car (cddddr x)))
(define (sixth x) (cadr (cddddr x))) (define (sixth x) (cadr (cddddr x)))
(define (seventh x) (caddr (cddddr x))) (define (seventh x) (caddr (cddddr x)))
(define (eighth x) (cadddr (cddddr x))) (define (eighth x) (cadddr (cddddr x)))
(define (ninth x) (car (cddddr (cddddr x)))) (define (ninth x) (car (cddddr (cddddr x))))
(define (tenth x) (cadr (cddddr (cddddr x)))) (define (tenth x) (cadr (cddddr (cddddr x))))
(define (car+cdr pair) (values (car pair) (cdr pair))) (define (car+cdr pair) (values (car pair) (cdr pair)))
;; take & drop ;; take & drop
(define (take lis k) (define (take lis k)
(check-arg integer? k 'take) (check-arg integer? k 'take)
(let recur ((lis lis) (k k)) (let recur ((lis lis) (k k))
(if (zero? k) '() (if (zero? k) '()
(cons (car lis) (cons (car lis)
(recur (cdr lis) (- k 1)))))) (recur (cdr lis) (- k 1))))))
(define (drop lis k) (define (drop lis k)
(check-arg integer? k 'drop) (check-arg integer? k 'drop)
(let iter ((lis lis) (k k)) (let iter ((lis lis) (k k))
(if (zero? k) lis (iter (cdr lis) (- k 1))))) (if (zero? k) lis (iter (cdr lis) (- k 1)))))
#; #;
(define (take! lis k) (define (take! lis k)
(check-arg integer? k 'take!) (check-arg integer? k 'take!)
(if (zero? k) '() (if (zero? k) '()
(begin (set-cdr! (drop lis (- k 1)) '()) (begin (set-cdr! (drop lis (- k 1)) '())
lis))) lis)))
;; TAKE-RIGHT and DROP-RIGHT work by getting two pointers into the list, ;; TAKE-RIGHT and DROP-RIGHT work by getting two pointers into the list,
;; off by K, then chasing down the list until the lead pointer falls off ;; off by K, then chasing down the list until the lead pointer falls off
;; the end. ;; the end.
(define (take-right lis k) (define (take-right lis k)
(check-arg integer? k 'take-right) (check-arg integer? k 'take-right)
(let lp ((lag lis) (lead (drop lis k))) (let lp ((lag lis) (lead (drop lis k)))
(if (pair? lead) (if (pair? lead)
(lp (cdr lag) (cdr lead)) (lp (cdr lag) (cdr lead))
lag))) lag)))
(define (drop-right lis k) (define (drop-right lis k)
(check-arg integer? k 'drop-right) (check-arg integer? k 'drop-right)
(let recur ((lag lis) (lead (drop lis k))) (let recur ((lag lis) (lead (drop lis k)))
(if (pair? lead) (if (pair? lead)
(cons (car lag) (recur (cdr lag) (cdr lead))) (cons (car lag) (recur (cdr lag) (cdr lead)))
'()))) '())))
;; In this function, LEAD is actually K+1 ahead of LAG. This lets ;; In this function, LEAD is actually K+1 ahead of LAG. This lets
;; us stop LAG one step early, in time to smash its cdr to (). ;; us stop LAG one step early, in time to smash its cdr to ().
#; #;
(define (drop-right! lis k) (define (drop-right! lis k)
(check-arg integer? k 'drop-right!) (check-arg integer? k 'drop-right!)
(let ((lead (drop lis k))) (let ((lead (drop lis k)))
(if (pair? lead) (if (pair? lead)
(let lp ((lag lis) (lead (cdr lead))) ; Standard case (let lp ((lag lis) (lead (cdr lead))) ; Standard case
(if (pair? lead) (if (pair? lead)
(lp (cdr lag) (cdr lead)) (lp (cdr lag) (cdr lead))
(begin (set-cdr! lag '()) (begin (set-cdr! lag '())
lis))) lis)))
'()))) ; Special case dropping everything -- no cons to side-effect. '()))) ; Special case dropping everything -- no cons to side-effect.
(define (split-at x k) (define (split-at x k)
(check-arg integer? k 'split-at) (check-arg integer? k 'split-at)
(let recur ((lis x) (k k)) (let recur ((lis x) (k k))
(if (zero? k) (values '() lis) (if (zero? k) (values '() lis)
(receive (prefix suffix) (recur (cdr lis) (- k 1)) (receive (prefix suffix) (recur (cdr lis) (- k 1))
(values (cons (car lis) prefix) suffix))))) (values (cons (car lis) prefix) suffix)))))
#; #;
(define (split-at! x k) (define (split-at! x k)
(check-arg integer? k 'split-at!) (check-arg integer? k 'split-at!)
(if (zero? k) (values '() x) (if (zero? k) (values '() x)
(let* ((prev (drop x (- k 1))) (let* ((prev (drop x (- k 1)))
@ -136,15 +132,12 @@
(set-cdr! prev '()) (set-cdr! prev '())
(values x suffix)))) (values x suffix))))
(define (last lis) (car (last-pair lis)))
(define (last lis) (car (last-pair lis))) (define (last-pair lis)
(define (last-pair lis)
(check-arg pair? lis 'last-pair) (check-arg pair? lis 'last-pair)
(let lp ((lis lis)) (let lp ((lis lis))
(let ((tail (cdr lis))) (let ((tail (cdr lis)))
(if (pair? tail) (lp tail) lis)))) (if (pair? tail) (lp tail) lis))))
)
;;; selector.ss ends here ;;; selector.ss ends here

73
collects/srfi/1/util.ss
View File

@ -32,41 +32,40 @@
;; hold me liable for its use. Please send bug reports to shivers@ai.mit.edu. ;; hold me liable for its use. Please send bug reports to shivers@ai.mit.edu.
;; -Olin ;; -Olin
(module util #lang mzscheme
mzscheme
(require srfi/optional (require srfi/optional
"predicate.ss" "predicate.ss"
"selector.ss") "selector.ss"
(require srfi/8/receive) srfi/8/receive)
(provide %cdrs (provide %cdrs
%cars+ %cars+
%cars+cdrs %cars+cdrs
%cars+cdrs+ %cars+cdrs+
%cars+cdrs/no-test) %cars+cdrs/no-test)
;; Fold/map internal utilities ;; Fold/map internal utilities
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; These little internal utilities are used by the general ;; These little internal utilities are used by the general
;; fold & mapper funs for the n-ary cases . It'd be nice if they got inlined. ;; fold & mapper funs for the n-ary cases . It'd be nice if they got inlined.
;; One the other hand, the n-ary cases are painfully inefficient as it is. ;; One the other hand, the n-ary cases are painfully inefficient as it is.
;; An aggressive implementation should simply re-write these functions ;; An aggressive implementation should simply re-write these functions
;; for raw efficiency; I have written them for as much clarity, portability, ;; for raw efficiency; I have written them for as much clarity, portability,
;; and simplicity as can be achieved. ;; and simplicity as can be achieved.
;; ;;
;; I use the dreaded call/cc to do local aborts. A good compiler could ;; I use the dreaded call/cc to do local aborts. A good compiler could
;; handle this with extreme efficiency. An implementation that provides ;; handle this with extreme efficiency. An implementation that provides
;; a one-shot, non-persistent continuation grabber could help the compiler ;; a one-shot, non-persistent continuation grabber could help the compiler
;; out by using that in place of the call/cc's in these routines. ;; out by using that in place of the call/cc's in these routines.
;; ;;
;; These functions have funky definitions that are precisely tuned to ;; These functions have funky definitions that are precisely tuned to
;; the needs of the fold/map procs -- for example, to minimize the number ;; the needs of the fold/map procs -- for example, to minimize the number
;; of times the argument lists need to be examined. ;; of times the argument lists need to be examined.
;; Return (map cdr lists). ;; Return (map cdr lists).
;; However, if any element of LISTS is empty, just abort and return '(). ;; However, if any element of LISTS is empty, just abort and return '().
(define (%cdrs lists) (define (%cdrs lists)
(call-with-escape-continuation (call-with-escape-continuation
(lambda (abort) (lambda (abort)
(let recur ((lists lists)) (let recur ((lists lists))
@ -76,15 +75,15 @@
(cons (cdr lis) (recur (cdr lists))))) (cons (cdr lis) (recur (cdr lists)))))
'()))))) '())))))
(define (%cars+ lists last-elt) ; (append! (map car lists) (list last-elt)) (define (%cars+ lists last-elt) ; (append! (map car lists) (list last-elt))
(let recur ((lists lists)) (let recur ((lists lists))
(if (pair? lists) (cons (caar lists) (recur (cdr lists))) (list last-elt)))) (if (pair? lists) (cons (caar lists) (recur (cdr lists))) (list last-elt))))
;; LISTS is a (not very long) non-empty list of lists. ;; LISTS is a (not very long) non-empty list of lists.
;; Return two lists: the cars & the cdrs of the lists. ;; Return two lists: the cars & the cdrs of the lists.
;; However, if any of the lists is empty, just abort and return [() ()]. ;; However, if any of the lists is empty, just abort and return [() ()].
(define (%cars+cdrs lists) (define (%cars+cdrs lists)
(call-with-escape-continuation (call-with-escape-continuation
(lambda (abort) (lambda (abort)
(let recur ((lists lists)) (let recur ((lists lists))
@ -96,9 +95,9 @@
(values (cons a cars) (cons d cdrs)))))) (values (cons a cars) (cons d cdrs))))))
(values '() '())))))) (values '() '()))))))
;; Like %CARS+CDRS, but we pass in a final elt tacked onto the end of the ;; Like %CARS+CDRS, but we pass in a final elt tacked onto the end of the
;; cars list. What a hack. ;; cars list. What a hack.
(define (%cars+cdrs+ lists cars-final) (define (%cars+cdrs+ lists cars-final)
(call-with-escape-continuation (call-with-escape-continuation
(lambda (abort) (lambda (abort)
(let recur ((lists lists)) (let recur ((lists lists))
@ -110,8 +109,8 @@
(values (cons a cars) (cons d cdrs)))))) (values (cons a cars) (cons d cdrs))))))
(values (list cars-final) '())))))) (values (list cars-final) '()))))))
;; Like %CARS+CDRS, but blow up if any list is empty. ;; Like %CARS+CDRS, but blow up if any list is empty.
(define (%cars+cdrs/no-test lists) (define (%cars+cdrs/no-test lists)
(let recur ((lists lists)) (let recur ((lists lists))
(if (pair? lists) (if (pair? lists)
(receive (list other-lists) (car+cdr lists) (receive (list other-lists) (car+cdr lists)
@ -120,6 +119,4 @@
(values (cons a cars) (cons d cdrs))))) (values (cons a cars) (cons d cdrs)))))
(values '() '())))) (values '() '()))))
)
;;; util.ss ends here ;;; util.ss ends here