You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
154 lines
4.6 KiB
Racket
154 lines
4.6 KiB
Racket
#lang racket/base
|
|
(require racket/contract net/url xml)
|
|
(require (only-in racket/list empty? range splitf-at dropf dropf-right))
|
|
(require (only-in racket/format ~a))
|
|
(require (only-in racket/string string-join))
|
|
(require (only-in racket/vector vector-member))
|
|
(require (only-in racket/set set set->list set?))
|
|
(module+ test (require rackunit))
|
|
|
|
(provide (all-defined-out))
|
|
|
|
|
|
|
|
;; general way of coercing to string
|
|
(define/contract (->string x)
|
|
(any/c . -> . string?)
|
|
(cond
|
|
[(string? x) x]
|
|
[(empty? x) ""]
|
|
[(symbol? x) (symbol->string x)]
|
|
[(number? x) (number->string x)]
|
|
[(path? x) (path->string x)]
|
|
[(char? x) (~a x)]
|
|
[(xexpr? x) (xexpr->string x)] ; put this last so other xexprish things don't get caught
|
|
[else (error (format "Can't make ~a into string" x))]))
|
|
|
|
(module+ test
|
|
(check-equal? (->string "foo") "foo")
|
|
(check-equal? (->string '()) "")
|
|
(check-equal? (->string 'foo) "foo")
|
|
(check-equal? (->string 123) "123")
|
|
(define file-name-as-text "foo.txt")
|
|
(check-equal? (->string (string->path file-name-as-text)) file-name-as-text)
|
|
(check-equal? (->string #\¶) "¶")
|
|
(check-equal? (->string '(foo "bar")) "<foo>bar</foo>"))
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
;; general way of coercing to a list
|
|
(define/contract (->list x)
|
|
(any/c . -> . list?)
|
|
(cond
|
|
[(list? x) x]
|
|
[(vector? x) (vector->list x)]
|
|
[(set? x) (set->list x)]
|
|
[else (list x)]))
|
|
|
|
(module+ test
|
|
(check-equal? (->list '(1 2 3)) '(1 2 3))
|
|
(check-equal? (->list (list->vector '(1 2 3))) '(1 2 3))
|
|
(check-equal? (->list (set 1 2 3)) '(3 2 1))
|
|
(check-equal? (->list "foo") (list "foo")))
|
|
|
|
;; general way of coercing to vector
|
|
(define (->vector x)
|
|
(any/c . -> . vector?)
|
|
; todo: on bad input, it will pop a list error rather than vector error
|
|
(cond
|
|
[(vector? x) x]
|
|
[else (list->vector (->list x))]))
|
|
|
|
|
|
|
|
;; general way of coercing to boolean
|
|
(define/contract (->boolean x)
|
|
(any/c . -> . boolean?)
|
|
;; in Racket, everything but #f is true
|
|
(if x #t #f))
|
|
|
|
(module+ test
|
|
(check-true (->boolean #t))
|
|
(check-false (->boolean #f))
|
|
(check-true (->boolean "#f"))
|
|
(check-true (->boolean "foo"))
|
|
(check-true (->boolean '()))
|
|
(check-true (->boolean '(1 2 3))))
|
|
|
|
|
|
(define/contract (has-length? x)
|
|
(any/c . -> . boolean?)
|
|
(ormap (λ(proc) (proc x)) (list list? string? symbol? vector? hash? set?)))
|
|
|
|
;; general way of asking for length
|
|
(define/contract (len x)
|
|
(has-length? . -> . integer?)
|
|
(cond
|
|
[(list? x) (length x)]
|
|
[(string? x) (string-length x)]
|
|
[(symbol? x) (len (->string x))]
|
|
[(vector? x) (len (->list x))]
|
|
[(hash? x) (len (hash-keys x))]
|
|
[(set? x) (len (->list x))]
|
|
[else #f]))
|
|
|
|
(module+ test
|
|
(check-equal? (len '(1 2 3)) 3)
|
|
(check-not-equal? (len '(1 2)) 3) ; len 2
|
|
(check-equal? (len "foo") 3)
|
|
(check-not-equal? (len "fo") 3) ; len 2
|
|
(check-equal? (len 'foo) 3)
|
|
(check-not-equal? (len 'fo) 3) ; len 2
|
|
(check-equal? (len (list->vector '(1 2 3))) 3)
|
|
(check-not-equal? (len (list->vector '(1 2))) 3) ; len 2
|
|
(check-equal? (len (set 1 2 3)) 3)
|
|
(check-not-equal? (len (set 1 2)) 3) ; len 2
|
|
(check-equal? (len (make-hash '((a . 1) (b . 2) (c . 3)))) 3)
|
|
(check-not-equal? (len (make-hash '((a . 1) (b . 2)))) 3)) ; len 2
|
|
|
|
|
|
|
|
|
|
|
|
|
|
;; trim from beginning & end of list
|
|
(define (trim items test-proc)
|
|
(list? procedure? . -> . list?)
|
|
(dropf-right (dropf items test-proc) test-proc))
|
|
|
|
(module+ test
|
|
; (check-equal? (trim (list "\n" " " 1 2 3 "\n") whitespace?) '(1 2 3))
|
|
(check-equal? (trim (list 1 3 2 4 5 6 8 9 13) odd?) '(2 4 5 6 8)))
|
|
|
|
|
|
|
|
;; split list into list of sublists using test-proc
|
|
(define/contract (splitf-at* xs split-test)
|
|
;; todo: better error message when split-test is not a predicate
|
|
(list? predicate/c . -> . (listof list?))
|
|
(define (&splitf-at* xs [acc '()]) ; use acc for tail recursion
|
|
(if (empty? xs)
|
|
;; reverse because accumulation is happening backward
|
|
;; (because I'm using cons to push latest match onto front of list)
|
|
(reverse acc)
|
|
(let-values ([(item rest)
|
|
;; drop matching elements from front
|
|
;; then split on nonmatching
|
|
;; = nonmatching item + other elements (which will start with matching)
|
|
(splitf-at (dropf xs split-test) (compose1 not split-test))])
|
|
;; recurse, and store new item in accumulator
|
|
(&splitf-at* rest (cons item acc)))))
|
|
|
|
;; trim off elements matching split-test
|
|
(&splitf-at* (trim xs split-test)))
|
|
|
|
(module+ test
|
|
; (check-equal? (splitf-at* '("foo" " " "bar" "\n" "\n" "ino") whitespace?) '(("foo")("bar")("ino")))
|
|
(check-equal? (splitf-at* '(1 2 3 4 5 6) even?) '((1)(3)(5))))
|
|
|
|
|