From f2210cb0e5cb64d43e67868c0bc20c671e72a49d Mon Sep 17 00:00:00 2001
From: David Thompson <dthompson2@worcester.edu>
Date: Wed, 16 Dec 2015 20:44:48 -0500
Subject: events: keyboard: Add additional predicates.

* sdl2/events.scm (keyboard-down-event?, keyboard-up-event?): New procedures.
---
 sdl2/events.scm | 12 ++++++++++++
 1 file changed, 12 insertions(+)

(limited to 'sdl2')

diff --git a/sdl2/events.scm b/sdl2/events.scm
index 1d40a38..edb9306 100644
--- a/sdl2/events.scm
+++ b/sdl2/events.scm
@@ -42,6 +42,8 @@
 
             make-keyboard-event
             keyboard-event?
+            keyboard-down-event?
+            keyboard-up-event?
             keyboard-event-timestamp
             keyboard-event-window-id
             keyboard-event-pressed?
@@ -133,6 +135,16 @@
   (scancode keyboard-event-scancode)
   (modifiers keyboard-event-modifiers))
 
+(define (keyboard-down-event? e)
+  "Return #t if E is a key press event."
+  (and (keyboard-event? e)
+       (keyboard-event-pressed? e)))
+
+(define (keyboard-up-event? e)
+  "Return #t if E is a key release event."
+  (and (keyboard-event? e)
+       (not (keyboard-event-pressed? e))))
+
 (define keycode-map
   (alist->hash-table
    `((,ffi:SDLK_UNKNOWN . unknown)
-- 
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