add slider GUI element

src/main.rs

@@ -489,6 +489,16 @@ struct Cells {
     cells: Vec<Cell>,
 }
 
+static mut CELL_UI: Option<&'static mut egui::Ui> = None;
+
+#[no_mangle]
+pub extern "C" fn __nac3_cells_slider(prev: f64) -> f64 {
+    let ui = unsafe { CELL_UI.as_mut().unwrap() };
+    let mut value = prev;
+    ui.add(egui::Slider::new(&mut value, 0.0..=100.0));
+    value
+}
+
 impl Cells {
     fn new() -> Self {
         Self {
@@ -541,7 +551,18 @@ impl Cells {
                 });
                 match &cell.result {
                     Ok(bin) => {
-                        ui.label(format!("{}", unsafe { bin.run_fn.unwrap()() }));
+                        let result = {
+                            unsafe {
+                                CELL_UI.replace(std::mem::transmute::<
+                                    &mut egui::Ui,
+                                    &'static mut egui::Ui,
+                                >(ui))
+                            };
+                            let result = unsafe { bin.run_fn.unwrap()() };
+                            unsafe { CELL_UI.take() };
+                            result
+                        };
+                        ui.label(format!("{}", result));
                     }
                     Err(msg) => {
                         if !msg.is_empty() {