flink-support

racket/typed/examples/roles/flink-support.rkt

@@ -0,0 +1,32 @@
+#lang racket
+
+(provide string->words
+         split-at/lenient-)
+
+(require (only-in racket/list
+                  split-at))
+(module+ test
+  (require rackunit))
+
+(define (string->words s)
+    (map (lambda (w) (string-trim w #px"\\p{P}")) (string-split s)))
+
+(module+ test
+  (check-equal? (string->words "good day sir")
+                (list "good" "day" "sir"))
+  (check-equal? (string->words "")
+                (list))
+  (check-equal? (string->words "good eve ma'am")
+                (list "good" "eve" "ma'am"))
+  (check-equal? (string->words "please sir. may I have another?")
+                (list "please" "sir" "may" "I" "have" "another"))
+  ;; TODO - currently fails
+  #;(check-equal? (string->words "but wait---there's more")
+                  (list "but" "wait" "there's" "more")))
+
+;; (Listof A) Nat -> (List (Listof A) (Listof A))
+;; like split-at but allow a number larger than the length of the list
+(define (split-at/lenient- lst n)
+  (define-values (a b)
+    (split-at lst (min n (length lst))))
+  (list a b))