|
|
|
#lang racket/base
|
|
|
|
(require (for-syntax
|
|
|
|
racket/base)
|
|
|
|
racket/list
|
|
|
|
racket/match
|
|
|
|
racket/function
|
|
|
|
"define.rkt")
|
|
|
|
|
|
|
|
(define (increasing-nonnegative-list? x)
|
|
|
|
(and (list? x) (or (empty? x) (apply < -1 x))))
|
|
|
|
|
|
|
|
(define+provide+safe (trimf xs test-proc)
|
|
|
|
(list? procedure? . -> . list?)
|
|
|
|
(unless (list? xs)
|
|
|
|
(raise-argument-error 'trimf "list?" xs))
|
|
|
|
(dropf-right (dropf xs test-proc) test-proc))
|
|
|
|
|
|
|
|
(define (slicef-and-filter-split-helper xs pred [separate-negated? #f])
|
|
|
|
(let loop ([xs xs][negating? #f][acc empty][negated-acc empty])
|
|
|
|
(match xs
|
|
|
|
[(? empty?) (if separate-negated?
|
|
|
|
(values (reverse acc) (reverse negated-acc))
|
|
|
|
(reverse acc))]
|
|
|
|
[(list* (? (if negating? (negate pred) pred) pred-xs) ... other-xs)
|
|
|
|
(cond
|
|
|
|
[(and negating? separate-negated?)
|
|
|
|
(loop other-xs
|
|
|
|
(not negating?)
|
|
|
|
acc
|
|
|
|
(match pred-xs
|
|
|
|
[(? empty?) negated-acc]
|
|
|
|
[_ (cons pred-xs negated-acc)]))]
|
|
|
|
[else
|
|
|
|
(loop other-xs
|
|
|
|
(not negating?)
|
|
|
|
(match pred-xs
|
|
|
|
[(? empty?) acc]
|
|
|
|
[_ (cons pred-xs acc)])
|
|
|
|
negated-acc)])])))
|
|
|
|
|
|
|
|
|
|
|
|
(define+provide+safe (slicef xs pred)
|
|
|
|
(list? procedure? . -> . (listof list?))
|
|
|
|
(unless (list? xs)
|
|
|
|
(raise-argument-error 'slicef "list?" xs))
|
|
|
|
(slicef-and-filter-split-helper xs pred))
|
|
|
|
|
|
|
|
(define+provide+safe (slicef-at xs pred [force? #f])
|
|
|
|
((list? procedure?) (boolean?) . ->* . (listof list?))
|
|
|
|
(unless (list? xs)
|
|
|
|
(raise-argument-error 'slicef-at "list?" xs))
|
|
|
|
(unless (procedure? pred)
|
|
|
|
(raise-argument-error 'slicef-at "procedure?" pred))
|
|
|
|
(let loop ([xs xs][acc empty])
|
|
|
|
(match xs
|
|
|
|
[(== empty) (reverse acc)]
|
|
|
|
[(list* (? pred pred-x) (? (negate pred) not-pred-xs) ... tail)
|
|
|
|
(loop tail (cons (cons pred-x not-pred-xs) acc))]
|
|
|
|
[(list* (? (negate pred) not-pred-xs) ... tail)
|
|
|
|
(loop tail (if force? acc (cons not-pred-xs acc)))])))
|
|
|
|
|
|
|
|
(define+provide+safe (slicef-after xs pred [force? #f])
|
|
|
|
((list? procedure?) (boolean?) . ->* . (listof list?))
|
|
|
|
(unless (list? xs)
|
|
|
|
(raise-argument-error 'slicef-after "list?" xs))
|
|
|
|
(unless (procedure? pred)
|
|
|
|
(raise-argument-error 'slicef-after "procedure?" pred))
|
|
|
|
(let loop ([xs xs][acc empty])
|
|
|
|
(match xs
|
|
|
|
[(== empty) (reverse acc)]
|
|
|
|
[(list* (? (negate pred) not-pred-xs) ... (? pred pred-x) tail)
|
|
|
|
(loop tail (cons (append not-pred-xs (list pred-x)) acc))]
|
|
|
|
[tail (loop empty (if force? acc (cons tail acc)))])))
|
|
|
|
|
|
|
|
(define+provide+safe (slice-at xs len [force? #f])
|
|
|
|
((list? exact-nonnegative-integer?) (boolean?) . ->* . (listof list?))
|
|
|
|
(unless (list? xs)
|
|
|
|
(raise-argument-error 'slice-at "list?" xs))
|
|
|
|
(unless (and (integer? len) (positive? len))
|
|
|
|
(raise-argument-error 'slice-at "positive integer for sublist length" len))
|
|
|
|
(let loop ([xs xs][slices empty])
|
|
|
|
(if (< (length xs) len)
|
|
|
|
(reverse (if (or force? (empty? xs))
|
|
|
|
slices
|
|
|
|
(cons xs slices)))
|
|
|
|
(match/values (split-at xs len)
|
|
|
|
[(subxs rest) (loop rest (cons subxs slices))]))))
|
|
|
|
|
|
|
|
(define+provide+safe (partition* pred xs)
|
|
|
|
(predicate/c list? . -> . (values list? list?))
|
|
|
|
(unless (list? xs)
|
|
|
|
(raise-argument-error 'partition* "list?" xs))
|
|
|
|
(slicef-and-filter-split-helper xs pred 'drop-negated))
|
|
|
|
|
|
|
|
(define+provide+safe (filter-split xs pred)
|
|
|
|
(list? predicate/c . -> . (listof list?))
|
|
|
|
(unless (list? xs)
|
|
|
|
(raise-argument-error 'filter-split "list?" xs))
|
|
|
|
;; same idea as slicef, but the negated items are dropped
|
|
|
|
(define-values (negated-pred-xs _) (partition* (negate pred) xs))
|
|
|
|
negated-pred-xs)
|
|
|
|
|
|
|
|
(define+provide+safe (frequency-hash xs)
|
|
|
|
(list? . -> . hash?)
|
|
|
|
(unless (list? xs)
|
|
|
|
(raise-argument-error 'frequency-hash "list?" xs))
|
|
|
|
(define counter (make-hash))
|
|
|
|
(for ([item (in-list xs)])
|
|
|
|
(hash-update! counter item add1 0))
|
|
|
|
counter)
|
|
|
|
|
|
|
|
(define (->list x)
|
|
|
|
(match x
|
|
|
|
[(? list? x) x]
|
|
|
|
[(? vector?) (vector->list x)]
|
|
|
|
[(? string?) (string->list x)]
|
|
|
|
[else (raise-argument-error '->list "item that can be converted to list" x)]))
|
|
|
|
|
|
|
|
(define+provide+safe (members-unique? x)
|
|
|
|
((or/c list? vector? string?) . -> . boolean?)
|
|
|
|
(match (->list x)
|
|
|
|
[(? list? x) (= (length (remove-duplicates x)) (length x))]
|
|
|
|
[_ (raise-argument-error 'members-unique? "list, vector, or string" x)]))
|
|
|
|
|
|
|
|
(define+provide+safe (members-unique?/error x)
|
|
|
|
((or/c list? vector? string?) . -> . boolean?)
|
|
|
|
(match (members-unique? x)
|
|
|
|
[(== #false)
|
|
|
|
(define duplicate-keys (filter values (hash-map (frequency-hash (->list x))
|
|
|
|
(λ (element freq) (and (> freq 1) element)))))
|
|
|
|
(error (string-append "members-unique? failed because " (if (= (length duplicate-keys) 1)
|
|
|
|
"item isn't"
|
|
|
|
"items aren't") " unique:") duplicate-keys)]
|
|
|
|
[result result]))
|
|
|
|
|
|
|
|
(provide+safe values->list)
|
|
|
|
(define-syntax (values->list stx)
|
|
|
|
(syntax-case stx ()
|
|
|
|
[(_ VALUES-EXPR) #'(call-with-values (λ () VALUES-EXPR) list)]))
|
|
|
|
|
|
|
|
(define+provide+safe (sublist xs i j)
|
|
|
|
(list? exact-nonnegative-integer? exact-nonnegative-integer? . -> . list?)
|
|
|
|
(unless (list? xs)
|
|
|
|
(raise-argument-error 'sublist "list?" xs))
|
|
|
|
(cond
|
|
|
|
[(> j (length xs)) (error 'sublist (format "ending index ~a exceeds length of list" j))]
|
|
|
|
[(>= j i) (for/list ([(x idx) (in-indexed xs)]
|
|
|
|
#:when (<= i idx (sub1 j)))
|
|
|
|
x)]
|
|
|
|
[else (raise-argument-error 'sublist (format "starting index larger than ending index" (list i j)))]))
|
|
|
|
|
|
|
|
(define+provide+safe (break-at xs bps-in)
|
|
|
|
(list? any/c . -> . (listof list?))
|
|
|
|
(unless (list? xs)
|
|
|
|
(raise-argument-error 'break-at "list" xs))
|
|
|
|
(define bps ((if (list? bps-in) values list) bps-in))
|
|
|
|
(when (ormap (λ (bp) (<= (length xs) bp)) bps)
|
|
|
|
(raise-argument-error 'break-at
|
|
|
|
(format "breakpoints not greater than or equal to input list length = ~a" (length xs)) bps))
|
|
|
|
(unless (increasing-nonnegative-list? bps)
|
|
|
|
(raise-argument-error 'break-at "increasing-nonnegative-list" bps))
|
|
|
|
;; easier to do back to front, because then the list index for each item won't change during the recursion
|
|
|
|
;; cons a zero onto bps (which may already start with zero) and then use that as the terminating condition
|
|
|
|
;; because breaking at zero means we've reached the start of the list
|
|
|
|
(let loop ([xs xs][bps (reverse (cons 0 bps))][acc empty])
|
|
|
|
(match bps
|
|
|
|
[(cons (? zero?) _) (cons xs acc)] ; return whatever's left, because no more splits are possible
|
|
|
|
[_ (match/values (split-at xs (car bps))
|
|
|
|
[(head tail) (loop head (cdr bps) (cons tail acc))])])))
|
|
|
|
|
|
|
|
(define (shift-base xs how-far fill-item cycle caller)
|
|
|
|
(unless (list? xs)
|
|
|
|
(raise-argument-error caller "list?" xs))
|
|
|
|
(define abs-how-far (if cycle
|
|
|
|
(modulo (abs how-far) (length xs))
|
|
|
|
(abs how-far)))
|
|
|
|
(define (make-fill thing) (if cycle thing (make-list abs-how-far fill-item)))
|
|
|
|
(cond
|
|
|
|
[(> abs-how-far (length xs))
|
|
|
|
(raise-argument-error caller
|
|
|
|
(format "index not larger than list length ~a" (length xs))
|
|
|
|
(* (if (eq? caller 'shift-left) -1 1) how-far))]
|
|
|
|
[(zero? how-far) xs]
|
|
|
|
[(positive? how-far)
|
|
|
|
(match/values (split-at-right xs abs-how-far)
|
|
|
|
[(head tail) (append (make-fill tail) head)])]
|
|
|
|
[else ; how-far is negative
|
|
|
|
(match/values (split-at xs abs-how-far)
|
|
|
|
[(head tail) (append tail (make-fill head))])]))
|
|
|
|
|
|
|
|
(define+provide+safe (shift xs how-far [fill-item #f] [cycle #f])
|
|
|
|
((list? integer?) (any/c boolean?) . ->* . list?)
|
|
|
|
(shift-base xs how-far fill-item cycle 'shift))
|
|
|
|
|
|
|
|
(define+provide+safe (shift-left xs how-far [fill-item #f] [cycle #f])
|
|
|
|
((list? integer?) (any/c boolean?) . ->* . list?)
|
|
|
|
(shift-base xs (- how-far) fill-item cycle 'shift-left))
|
|
|
|
|
|
|
|
(define+provide+safe (shift-cycle xs how-far)
|
|
|
|
(list? integer? . -> . list?)
|
|
|
|
(shift-base xs how-far #false #true 'shift-cycle))
|
|
|
|
|
|
|
|
(define+provide+safe (shift-left-cycle xs how-far)
|
|
|
|
(list? integer? . -> . list?)
|
|
|
|
(shift-base xs (- how-far) #false #true 'shift-left-cycle))
|
|
|
|
|
|
|
|
(define+provide+safe (shifts xs how-fars [fill-item #f] [cycle #f])
|
|
|
|
((list? (listof integer?)) (any/c boolean?) . ->* . (listof list?))
|
|
|
|
(unless (list? xs)
|
|
|
|
(raise-argument-error 'shifts "list?" xs))
|
|
|
|
(map (λ (how-far) (shift xs how-far fill-item cycle)) how-fars))
|
|
|
|
|
|
|
|
(define+provide+safe (shift/values xs shift-amount-or-amounts [fill-item #f] [cycle #f])
|
|
|
|
((list? (or/c (listof integer?) integer?)) (any/c boolean?) . ->* . any)
|
|
|
|
(apply values ((if (list? shift-amount-or-amounts)
|
|
|
|
shifts
|
|
|
|
shift) xs shift-amount-or-amounts fill-item cycle)))
|