fix updated defs not being applied properly to VM in frontend and backend

this fixes the case where

	(def botsbuildbots (fn () (botsbuildbots))) (botsbuildbots)

would not run properly (return with a "set def index out of bounds" error)

also make exceptions store String instead of &'static str for better error reporting

closes #33

crates/haku/src/render.rs

@@ -43,8 +43,8 @@ impl<'a> Renderer<'a> {
         }
     }
 
-    fn create_exception(_vm: &Vm, _at: Value, message: &'static str) -> Exception {
-        Exception { message }
+    fn create_exception(vm: &Vm, _at: Value, message: &'static str) -> Exception {
+        vm.create_exception(message)
     }
 
     fn transform(&self) -> Transform {

crates/haku/src/vm.rs

@@ -4,7 +4,7 @@ use core::{
     iter,
 };
 
-use alloc::vec::Vec;
+use alloc::{string::String, vec::Vec};
 
 use crate::{
     bytecode::{self, Defs, Opcode, CAPTURE_CAPTURE, CAPTURE_LOCAL},
@@ -416,8 +416,10 @@ impl Vm {
         }
     }
 
-    pub fn create_exception(&self, message: &'static str) -> Exception {
-        Exception { message }
+    pub fn create_exception(&self, message: impl Into<String>) -> Exception {
+        Exception {
+            message: message.into(),
+        }
     }
 
     pub fn track_array<T>(&mut self, array: &[T]) -> Result<(), Exception> {
@@ -492,15 +494,15 @@ impl FnArgs {
     }
 }
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Exception {
-    pub message: &'static str,
+    pub message: String,
 }
 
 impl From<bytecode::ReadError> for Exception {
     fn from(_: bytecode::ReadError) -> Self {
         Self {
-            message: "corrupted bytecode",
+            message: "corrupted bytecode".into(),
         }
     }
 }

crates/haku/tests/language.rs

@@ -167,6 +167,19 @@ fn def_mutually_recursive() {
     expect_number(code, 14.0, 0.0001);
 }
 
+#[test]
+fn def_botsbuildbots() {
+    let result = eval("(def botsbuildbots (fn () (botsbuildbots))) (botsbuildbots)");
+    if let Err(error) = result {
+        assert_eq!(
+            error.to_string(),
+            "Exception {\n    message: \"too much recursion\",\n}"
+        );
+    } else {
+        panic!("error expected");
+    }
+}
+
 #[test]
 fn let_single() {
     let code = r#"