bjogui/examples/counter.bjo

;; This Source Code Form is subject to the terms of the Mozilla Public
;; License, v. 2.0. If a copy of the MPL was not distributed with this
;; file, You can obtain one at http://mozilla.org/MPL/2.0/.

;; bjogui/examples/counter.bjo — a counter and a greeting in a window.
;;
;;     bjo run examples/counter.bjo

(import (std prelude))
(import (bjogui view))
(import (bjogui app))

(type (: Msg (Union Inc Dec (: Typed string))))
(type (: Model (Record (: count int) (: name string))))

(: gui-update (-> Msg Model (Tuple Model (List (Event Msg)))))
(defun (gui-update msg m)
  (next
    (match msg
      (Inc (record-set m (count (+ (.count m) 1))))
      (Dec (record-set m (count (- (.count m) 1))))
      ((Typed s) (record-set m (name s))))))

(: view (-> Model (View Msg)))
(defun (view m)
  (column #:spacing 8.0 #:margin 16.0
    (text-input (.name m) Typed #:placeholder "Your name")
    (text #"Hello, ${(if (string-empty? (.name m)) "stranger" (.name m))}!" #:size 18.0)
    (row #:spacing 8.0
      (button "-" Dec #:width 40.0)
      (text #"${(.count m)}" #:size 18.0 #:margin 4.0)
      (button "+" Inc #:width 40.0))))

(defun (main)
  (run-app (Model (count 0) (name "")) gui-update view #:title "Counter" #:width 320.0 #:height 200.0))