scaffolding for char callback

ffi/export.h

@@ -158,6 +158,7 @@ extern "C" {
 #endif
 
 MLLIB_PUBLIC(void mltonFramebufferSizeCallback (Int32 x0, Int32 x1);)
+MLLIB_PUBLIC(void mltonCharCallback (Word32 x0);)
 
 #undef MLLIB_PRIVATE
 #undef MLLIB_PUBLIC

ffi/glfw-input.c

@@ -16,3 +16,11 @@ void setFramebufferSizeCallback(GLFWwindow* window) {
   glfwSetFramebufferSizeCallback(window, framebufferSizeCallback);
 }
 
+void charCallback(GLFWwindow* window, unsigned int codepoint) {
+  mltonCharCallback(codepoint);
+}
+
+void setCharCallback(GLFWwindow* window) {
+  glfwSetCharCallback(window, charCallback);
+}
+

ffi/glfw-input.sml

@@ -19,4 +19,9 @@ struct
     _export "mltonFramebufferSizeCallback" public : (int * int -> unit) -> unit;
   val setFramebufferSizeCallback =
     _import "setFramebufferSizeCallback" public : window -> unit;
+
+  val exportCharCallback =
+    _export "mltonCharCallback" public : (Word32.word -> unit) -> unit;
+  val setCharCallback =
+    _import "setCharCallback" public : window -> unit;
 end