refactor & fixed assembler path handling

emulator/src/emulator/ui/editor.rs

@@ -346,12 +346,24 @@ impl Editor {
             // builds the current file
             if ui.button("Build").clicked() && !self.unsaved {
                 if let Some(path) = &self.path {
-                    let instructions = match assemble(path) {
-                        Ok(instructions) => instructions,
-                        Err(error) => {
+                    let mut assembler = CompilerEngine::new();
+                    if let Err(error) = assembler.assemble(path) {
+                        self.error = Some(format!("Failed to assemble: {error:?}"));
+                        return;
+                    }
+
+                    let instructions = match assembler.result() {
+                        Some(Ok(instructions)) => instructions,
+                        Some(Err(error)) => {
                             self.error = Some(format!("Failed to assemble: {error:?}"));
                             return;
                         }
+                        None => {
+                            self.error = Some(
+                                "Failed to assemble: No result available".to_string(),
+                            );
+                            return;
+                        }
                     };
 
                     self.output = instructions