Simple IRC parser, tries to replicate https://github.com/Tehnix/HsIRCParser/blob/master/HsIRCParser.hs made by @Tehnix

parser.rkt

#lang racket

(provide split-message
         get-nick
         get-host
         get-chan
         get-action)

(define (split-message s) 
  (let ([ss (regexp-split #rx":" s)])
    (match ss
      [(list " " _ ...) (cdr ss)]
      [_ ss])))

(define (split-bang s)
  (regexp-split #rx"!" s))

(define (split-at s)
  (regexp-split #rx"@" s))

(define (get-nick ss)
  (regexp-replace #rx"[@~!&]" (car (split-bang (car ss))) ""))

(define (get-host ss)
  (car (string-split
    (cadr (split-at
      (cadr (split-bang (car ss))))))))

(define (get-chan ss)
  (if (null? ss)
    "" ; FIXME
    (if (chan? (car ss))
      (car ss)
      (get-chan (cdr ss)))))

(define (chan? s)
  (match s
    [(regexp #rx"^#.") #t]
    [_ #f]))

(define (get-action ss)
  (cadr (string-split (car ss))))