Public API and docs

src/stl/runtime_error.rs

@@ -0,0 +1,32 @@
+use std::fmt::Display;
+use std::rc::Rc;
+
+use crate::foreign::ExternError;
+
+/// Some external event prevented the operation from succeeding
+#[derive(Clone)]
+pub struct RuntimeError {
+  message: String,
+  operation: &'static str,
+}
+
+impl RuntimeError {
+  pub fn fail<T>(
+    message: String,
+    operation: &'static str,
+  ) -> Result<T, Rc<dyn ExternError>> {
+    return Err(Self { message, operation }.into_extern());
+  }
+
+  pub fn ext(message: String, operation: &'static str) -> Rc<dyn ExternError> {
+    return Self { message, operation }.into_extern();
+  }
+}
+
+impl Display for RuntimeError {
+  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    write!(f, "Error while {}: {}", self.operation, self.message)
+  }
+}
+
+impl ExternError for RuntimeError {}