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.
23 lines
811 B
Racket
23 lines
811 B
Racket
#lang racket/base
|
|
(require racket/contract)
|
|
(require "coerce.rkt" "container.rkt" "len.rkt" "try.rkt")
|
|
|
|
(provide starts-with? ends-with? stringish?)
|
|
|
|
;; stringish: data type that can be trivially converted to string
|
|
;; todo: merge this with pathish
|
|
(define/contract (stringish? x)
|
|
(any/c . -> . boolean?)
|
|
(try (->boolean (->string x)) (except [exn:fail? (λ(e) #f)])))
|
|
|
|
;; python-style string testers
|
|
(define/contract (starts-with? str starter)
|
|
(stringish? stringish? . -> . boolean?)
|
|
(let ([str (->string str)]
|
|
[starter (->string starter)])
|
|
(and (<= (len starter) (len str)) (equal? (get str 0 (len starter)) starter))))
|
|
|
|
|
|
(define/contract (ends-with? str ender)
|
|
(string? string? . -> . boolean?)
|
|
(and (<= (len ender) (len str)) (equal? (get str (- (len str) (len ender)) 'end) ender))) |