feat: error handling

evaluator/nixjit_error/src/lib.rs

@@ -32,11 +32,17 @@ pub enum Error {
     ResolutionError(String),
 
     /// An error occurred during the final evaluation of the LIR. This covers
-    /// all runtime errors, such as type mismatches (e.g., adding a string to
-    /// an integer), division by zero, or failed `assert` statements.
+    /// all unrecoverable runtime errors, such as type mismatches (e.g., adding
+    /// a string to an integer), division by zero, or primitive operation
+    /// argument arity mismatch
     #[error("error occurred during evaluation stage: {0}")]
     EvalError(String),
 
+    /// Represents an error that can be generated by `throw` or `assert`, and
+    /// can be caught by `builtins.tryEval`.
+    #[error("{0}")]
+    Catchable(String),
+
     /// A catch-all for any error that does not fit into the other categories.
     #[error("an unknown or unexpected error occurred")]
     Unknown,