(define-module (runewidth graphemes stream)
  #:use-module (srfi srfi-41)
  #:use-module (srfi srfi-9 gnu)
  #:export (make-grapheme

            input->grapheme-stream))

(define-immutable-record-type <grapheme>
  (make-grapheme glyphs width sentence-end? word-end?)
  grapheme?
  (glyphs grapheme-glyphs)
  (width grapheme-width)
  (sentence-end? grapheme-sentence-end?)
  (word-end? grapheme-word-end?))

(define-stream (input->grapheme-stream port)
  (unless port
    (set! port (current-input-port)))

  (define gr (make-grapheme glyphs width sentence-end? word-end?))

  (stream-cons c (input->grapheme-stream port)))