#lang racket

(define emoji
  (make-hasheqv
   '((#\space . ":large_blue_diamond:")
     (#\$ . ":heart:"))))

(for ([c (in-string "abcdefghijklmnopqrstuvwxyz")])
  (hash-set! emoji c (format ":regional_indicator_~a:" c))
  (hash-set! emoji (char-upcase c) (format ":regional_indicator_~a:" c)))

(define (->emoji c)
  (cond
    [(string? c) (map ->emoji (string->list c))]
    [(hash-has-key? emoji c) (hash-ref emoji c)]
    [else (string c)]))

(define (in-prompt-lines prompt)
  (stream-cons
   (begin (display prompt) (read-line))
   (in-prompt-lines prompt)))

(for ([s (in-prompt-lines "-> ")]
      #:break (zero? (string-length s)))
  (displayln (string-join (->emoji s) " ")))