diff --git a/pkg/rudus.d.ts b/pkg/rudus.d.ts
index eaec74d..b5e984a 100644
--- a/pkg/rudus.d.ts
+++ b/pkg/rudus.d.ts
@@ -11,11 +11,11 @@ export interface InitOutput {
   readonly __externref_table_alloc: () => number;
   readonly __wbindgen_export_2: WebAssembly.Table;
   readonly __wbindgen_free: (a: number, b: number, c: number) => void;
+  readonly __wbindgen_export_4: WebAssembly.Table;
   readonly __wbindgen_malloc: (a: number, b: number) => number;
   readonly __wbindgen_realloc: (a: number, b: number, c: number, d: number) => number;
-  readonly __wbindgen_export_6: WebAssembly.Table;
-  readonly closure355_externref_shim: (a: number, b: number, c: any) => void;
-  readonly closure368_externref_shim: (a: number, b: number, c: any, d: any) => void;
+  readonly closure354_externref_shim: (a: number, b: number, c: any) => void;
+  readonly closure377_externref_shim: (a: number, b: number, c: any, d: any) => void;
   readonly __wbindgen_start: () => void;
 }
 
diff --git a/pkg/rudus.js b/pkg/rudus.js
index 1bfc99b..1b02a9a 100644
--- a/pkg/rudus.js
+++ b/pkg/rudus.js
@@ -17,6 +17,22 @@ function handleError(f, args) {
     }
 }
 
+function logError(f, args) {
+    try {
+        return f.apply(this, args);
+    } catch (e) {
+        let error = (function () {
+            try {
+                return e instanceof Error ? `${e.message}\n\nStack:\n${e.stack}` : e.toString();
+            } catch(_) {
+                return "<failed to stringify thrown value>";
+            }
+        }());
+        console.error("wasm-bindgen: imported JS function that was not marked as `catch` threw an error:", error);
+        throw e;
+    }
+}
+
 const cachedTextDecoder = (typeof TextDecoder !== 'undefined' ? new TextDecoder('utf-8', { ignoreBOM: true, fatal: true }) : { decode: () => { throw Error('TextDecoder not available') } } );
 
 if (typeof TextDecoder !== 'undefined') { cachedTextDecoder.decode(); };
@@ -35,6 +51,112 @@ function getStringFromWasm0(ptr, len) {
     return cachedTextDecoder.decode(getUint8ArrayMemory0().subarray(ptr, ptr + len));
 }
 
+function isLikeNone(x) {
+    return x === undefined || x === null;
+}
+
+function _assertBoolean(n) {
+    if (typeof(n) !== 'boolean') {
+        throw new Error(`expected a boolean argument, found ${typeof(n)}`);
+    }
+}
+
+const CLOSURE_DTORS = (typeof FinalizationRegistry === 'undefined')
+    ? { register: () => {}, unregister: () => {} }
+    : new FinalizationRegistry(state => {
+    wasm.__wbindgen_export_4.get(state.dtor)(state.a, state.b)
+});
+
+function makeMutClosure(arg0, arg1, dtor, f) {
+    const state = { a: arg0, b: arg1, cnt: 1, dtor };
+    const real = (...args) => {
+        // First up with a closure we increment the internal reference
+        // count. This ensures that the Rust closure environment won't
+        // be deallocated while we're invoking it.
+        state.cnt++;
+        const a = state.a;
+        state.a = 0;
+        try {
+            return f(a, state.b, ...args);
+        } finally {
+            if (--state.cnt === 0) {
+                wasm.__wbindgen_export_4.get(state.dtor)(a, state.b);
+                CLOSURE_DTORS.unregister(state);
+            } else {
+                state.a = a;
+            }
+        }
+    };
+    real.original = state;
+    CLOSURE_DTORS.register(real, state, state);
+    return real;
+}
+
+function debugString(val) {
+    // primitive types
+    const type = typeof val;
+    if (type == 'number' || type == 'boolean' || val == null) {
+        return  `${val}`;
+    }
+    if (type == 'string') {
+        return `"${val}"`;
+    }
+    if (type == 'symbol') {
+        const description = val.description;
+        if (description == null) {
+            return 'Symbol';
+        } else {
+            return `Symbol(${description})`;
+        }
+    }
+    if (type == 'function') {
+        const name = val.name;
+        if (typeof name == 'string' && name.length > 0) {
+            return `Function(${name})`;
+        } else {
+            return 'Function';
+        }
+    }
+    // objects
+    if (Array.isArray(val)) {
+        const length = val.length;
+        let debug = '[';
+        if (length > 0) {
+            debug += debugString(val[0]);
+        }
+        for(let i = 1; i < length; i++) {
+            debug += ', ' + debugString(val[i]);
+        }
+        debug += ']';
+        return debug;
+    }
+    // Test for built-in
+    const builtInMatches = /\[object ([^\]]+)\]/.exec(toString.call(val));
+    let className;
+    if (builtInMatches && builtInMatches.length > 1) {
+        className = builtInMatches[1];
+    } else {
+        // Failed to match the standard '[object ClassName]'
+        return toString.call(val);
+    }
+    if (className == 'Object') {
+        // we're a user defined class or Object
+        // JSON.stringify avoids problems with cycles, and is generally much
+        // easier than looping through ownProperties of `val`.
+        try {
+            return 'Object(' + JSON.stringify(val) + ')';
+        } catch (_) {
+            return 'Object';
+        }
+    }
+    // errors
+    if (val instanceof Error) {
+        return `${val.name}: ${val.message}\n${val.stack}`;
+    }
+    // TODO we could test for more things here, like `Set`s and `Map`s.
+    return className;
+}
+
 let WASM_VECTOR_LEN = 0;
 
 const cachedTextEncoder = (typeof TextEncoder !== 'undefined' ? new TextEncoder('utf-8') : { encode: () => { throw Error('TextEncoder not available') } } );
@@ -54,6 +176,8 @@ const encodeString = (typeof cachedTextEncoder.encodeInto === 'function'
 
 function passStringToWasm0(arg, malloc, realloc) {
 
+    if (typeof(arg) !== 'string') throw new Error(`expected a string argument, found ${typeof(arg)}`);
+
     if (realloc === undefined) {
         const buf = cachedTextEncoder.encode(arg);
         const ptr = malloc(buf.length, 1) >>> 0;
@@ -82,7 +206,7 @@ function passStringToWasm0(arg, malloc, realloc) {
         ptr = realloc(ptr, len, len = offset + arg.length * 3, 1) >>> 0;
         const view = getUint8ArrayMemory0().subarray(ptr + offset, ptr + len);
         const ret = encodeString(arg, view);
-
+        if (ret.read !== arg.length) throw new Error('failed to pass whole string');
         offset += ret.written;
         ptr = realloc(ptr, len, offset, 1) >>> 0;
     }
@@ -99,41 +223,6 @@ function getDataViewMemory0() {
     }
     return cachedDataViewMemory0;
 }
-
-function isLikeNone(x) {
-    return x === undefined || x === null;
-}
-
-const CLOSURE_DTORS = (typeof FinalizationRegistry === 'undefined')
-    ? { register: () => {}, unregister: () => {} }
-    : new FinalizationRegistry(state => {
-    wasm.__wbindgen_export_6.get(state.dtor)(state.a, state.b)
-});
-
-function makeMutClosure(arg0, arg1, dtor, f) {
-    const state = { a: arg0, b: arg1, cnt: 1, dtor };
-    const real = (...args) => {
-        // First up with a closure we increment the internal reference
-        // count. This ensures that the Rust closure environment won't
-        // be deallocated while we're invoking it.
-        state.cnt++;
-        const a = state.a;
-        state.a = 0;
-        try {
-            return f(a, state.b, ...args);
-        } finally {
-            if (--state.cnt === 0) {
-                wasm.__wbindgen_export_6.get(state.dtor)(a, state.b);
-                CLOSURE_DTORS.unregister(state);
-            } else {
-                state.a = a;
-            }
-        }
-    };
-    real.original = state;
-    CLOSURE_DTORS.register(real, state, state);
-    return real;
-}
 /**
  * @param {string} src
  * @returns {Promise<void>}
@@ -145,12 +234,19 @@ export function ludus(src) {
     return ret;
 }
 
-function __wbg_adapter_18(arg0, arg1, arg2) {
-    wasm.closure355_externref_shim(arg0, arg1, arg2);
+function _assertNum(n) {
+    if (typeof(n) !== 'number') throw new Error(`expected a number argument, found ${typeof(n)}`);
+}
+function __wbg_adapter_20(arg0, arg1, arg2) {
+    _assertNum(arg0);
+    _assertNum(arg1);
+    wasm.closure354_externref_shim(arg0, arg1, arg2);
 }
 
-function __wbg_adapter_44(arg0, arg1, arg2, arg3) {
-    wasm.closure368_externref_shim(arg0, arg1, arg2, arg3);
+function __wbg_adapter_40(arg0, arg1, arg2, arg3) {
+    _assertNum(arg0);
+    _assertNum(arg1);
+    wasm.closure377_externref_shim(arg0, arg1, arg2, arg3);
 }
 
 async function __wbg_load(module, imports) {
@@ -195,17 +291,6 @@ function __wbg_get_imports() {
         const ret = arg0.call(arg1, arg2);
         return ret;
     }, arguments) };
-    imports.wbg.__wbg_error_7534b8e9a36f1ab4 = function(arg0, arg1) {
-        let deferred0_0;
-        let deferred0_1;
-        try {
-            deferred0_0 = arg0;
-            deferred0_1 = arg1;
-            console.error(getStringFromWasm0(arg0, arg1));
-        } finally {
-            wasm.__wbindgen_free(deferred0_0, deferred0_1, 1);
-        }
-    };
     imports.wbg.__wbg_io_5a3c8ea72d8c6ea3 = function() { return handleError(function (arg0, arg1) {
         let deferred0_0;
         let deferred0_1;
@@ -218,17 +303,17 @@ function __wbg_get_imports() {
             wasm.__wbindgen_free(deferred0_0, deferred0_1, 1);
         }
     }, arguments) };
-    imports.wbg.__wbg_log_11652c6a56eeddfb = function(arg0, arg1) {
+    imports.wbg.__wbg_log_11652c6a56eeddfb = function() { return logError(function (arg0, arg1) {
         console.log(getStringFromWasm0(arg0, arg1));
-    };
-    imports.wbg.__wbg_new_23a2665fac83c611 = function(arg0, arg1) {
+    }, arguments) };
+    imports.wbg.__wbg_new_23a2665fac83c611 = function() { return logError(function (arg0, arg1) {
         try {
             var state0 = {a: arg0, b: arg1};
             var cb0 = (arg0, arg1) => {
                 const a = state0.a;
                 state0.a = 0;
                 try {
-                    return __wbg_adapter_44(a, state0.b, arg0, arg1);
+                    return __wbg_adapter_40(a, state0.b, arg0, arg1);
                 } finally {
                     state0.a = a;
                 }
@@ -238,65 +323,54 @@ function __wbg_get_imports() {
         } finally {
             state0.a = state0.b = 0;
         }
-    };
-    imports.wbg.__wbg_new_8a6f238a6ece86ea = function() {
-        const ret = new Error();
-        return ret;
-    };
-    imports.wbg.__wbg_newnoargs_105ed471475aaf50 = function(arg0, arg1) {
+    }, arguments) };
+    imports.wbg.__wbg_newnoargs_105ed471475aaf50 = function() { return logError(function (arg0, arg1) {
         const ret = new Function(getStringFromWasm0(arg0, arg1));
         return ret;
-    };
-    imports.wbg.__wbg_now_8dddb61fa4928554 = function() {
+    }, arguments) };
+    imports.wbg.__wbg_now_8dddb61fa4928554 = function() { return logError(function () {
         const ret = Date.now();
         return ret;
-    };
-    imports.wbg.__wbg_queueMicrotask_97d92b4fcc8a61c5 = function(arg0) {
+    }, arguments) };
+    imports.wbg.__wbg_queueMicrotask_97d92b4fcc8a61c5 = function() { return logError(function (arg0) {
         queueMicrotask(arg0);
-    };
-    imports.wbg.__wbg_queueMicrotask_d3219def82552485 = function(arg0) {
+    }, arguments) };
+    imports.wbg.__wbg_queueMicrotask_d3219def82552485 = function() { return logError(function (arg0) {
         const ret = arg0.queueMicrotask;
         return ret;
-    };
-    imports.wbg.__wbg_random_57c118f142535bb6 = function() {
+    }, arguments) };
+    imports.wbg.__wbg_random_57c118f142535bb6 = function() { return logError(function () {
         const ret = Math.random();
         return ret;
-    };
-    imports.wbg.__wbg_resolve_4851785c9c5f573d = function(arg0) {
+    }, arguments) };
+    imports.wbg.__wbg_resolve_4851785c9c5f573d = function() { return logError(function (arg0) {
         const ret = Promise.resolve(arg0);
         return ret;
-    };
-    imports.wbg.__wbg_stack_0ed75d68575b0f3c = function(arg0, arg1) {
-        const ret = arg1.stack;
-        const ptr1 = passStringToWasm0(ret, wasm.__wbindgen_malloc, wasm.__wbindgen_realloc);
-        const len1 = WASM_VECTOR_LEN;
-        getDataViewMemory0().setInt32(arg0 + 4 * 1, len1, true);
-        getDataViewMemory0().setInt32(arg0 + 4 * 0, ptr1, true);
-    };
-    imports.wbg.__wbg_static_accessor_GLOBAL_88a902d13a557d07 = function() {
+    }, arguments) };
+    imports.wbg.__wbg_static_accessor_GLOBAL_88a902d13a557d07 = function() { return logError(function () {
         const ret = typeof global === 'undefined' ? null : global;
         return isLikeNone(ret) ? 0 : addToExternrefTable0(ret);
-    };
-    imports.wbg.__wbg_static_accessor_GLOBAL_THIS_56578be7e9f832b0 = function() {
+    }, arguments) };
+    imports.wbg.__wbg_static_accessor_GLOBAL_THIS_56578be7e9f832b0 = function() { return logError(function () {
         const ret = typeof globalThis === 'undefined' ? null : globalThis;
         return isLikeNone(ret) ? 0 : addToExternrefTable0(ret);
-    };
-    imports.wbg.__wbg_static_accessor_SELF_37c5d418e4bf5819 = function() {
+    }, arguments) };
+    imports.wbg.__wbg_static_accessor_SELF_37c5d418e4bf5819 = function() { return logError(function () {
         const ret = typeof self === 'undefined' ? null : self;
         return isLikeNone(ret) ? 0 : addToExternrefTable0(ret);
-    };
-    imports.wbg.__wbg_static_accessor_WINDOW_5de37043a91a9c40 = function() {
+    }, arguments) };
+    imports.wbg.__wbg_static_accessor_WINDOW_5de37043a91a9c40 = function() { return logError(function () {
         const ret = typeof window === 'undefined' ? null : window;
         return isLikeNone(ret) ? 0 : addToExternrefTable0(ret);
-    };
-    imports.wbg.__wbg_then_44b73946d2fb3e7d = function(arg0, arg1) {
+    }, arguments) };
+    imports.wbg.__wbg_then_44b73946d2fb3e7d = function() { return logError(function (arg0, arg1) {
         const ret = arg0.then(arg1);
         return ret;
-    };
-    imports.wbg.__wbg_then_48b406749878a531 = function(arg0, arg1, arg2) {
+    }, arguments) };
+    imports.wbg.__wbg_then_48b406749878a531 = function() { return logError(function (arg0, arg1, arg2) {
         const ret = arg0.then(arg1, arg2);
         return ret;
-    };
+    }, arguments) };
     imports.wbg.__wbindgen_cb_drop = function(arg0) {
         const obj = arg0.original;
         if (obj.cnt-- == 1) {
@@ -304,11 +378,19 @@ function __wbg_get_imports() {
             return true;
         }
         const ret = false;
+        _assertBoolean(ret);
         return ret;
     };
-    imports.wbg.__wbindgen_closure_wrapper1080 = function(arg0, arg1, arg2) {
-        const ret = makeMutClosure(arg0, arg1, 356, __wbg_adapter_18);
+    imports.wbg.__wbindgen_closure_wrapper8119 = function() { return logError(function (arg0, arg1, arg2) {
+        const ret = makeMutClosure(arg0, arg1, 355, __wbg_adapter_20);
         return ret;
+    }, arguments) };
+    imports.wbg.__wbindgen_debug_string = function(arg0, arg1) {
+        const ret = debugString(arg1);
+        const ptr1 = passStringToWasm0(ret, wasm.__wbindgen_malloc, wasm.__wbindgen_realloc);
+        const len1 = WASM_VECTOR_LEN;
+        getDataViewMemory0().setInt32(arg0 + 4 * 1, len1, true);
+        getDataViewMemory0().setInt32(arg0 + 4 * 0, ptr1, true);
     };
     imports.wbg.__wbindgen_init_externref_table = function() {
         const table = wasm.__wbindgen_export_2;
@@ -322,10 +404,12 @@ function __wbg_get_imports() {
     };
     imports.wbg.__wbindgen_is_function = function(arg0) {
         const ret = typeof(arg0) === 'function';
+        _assertBoolean(ret);
         return ret;
     };
     imports.wbg.__wbindgen_is_undefined = function(arg0) {
         const ret = arg0 === undefined;
+        _assertBoolean(ret);
         return ret;
     };
     imports.wbg.__wbindgen_string_get = function(arg0, arg1) {
diff --git a/pkg/rudus_bg.wasm b/pkg/rudus_bg.wasm
index 8dda762..9b9a598 100644
--- a/pkg/rudus_bg.wasm
+++ b/pkg/rudus_bg.wasm
@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:1c853645770e84986b8ee1eca6c80549617e6836a3b832a18c717b0186e9ed75
-size 2703051
+oid sha256:e8e8b8752e877bfcad162074189d7d38423e458f5204400c409796841f8884e9
+size 16769183
diff --git a/pkg/rudus_bg.wasm.d.ts b/pkg/rudus_bg.wasm.d.ts
index ef098a3..2186b19 100644
--- a/pkg/rudus_bg.wasm.d.ts
+++ b/pkg/rudus_bg.wasm.d.ts
@@ -6,9 +6,9 @@ export const __wbindgen_exn_store: (a: number) => void;
 export const __externref_table_alloc: () => number;
 export const __wbindgen_export_2: WebAssembly.Table;
 export const __wbindgen_free: (a: number, b: number, c: number) => void;
+export const __wbindgen_export_4: WebAssembly.Table;
 export const __wbindgen_malloc: (a: number, b: number) => number;
 export const __wbindgen_realloc: (a: number, b: number, c: number, d: number) => number;
-export const __wbindgen_export_6: WebAssembly.Table;
-export const closure355_externref_shim: (a: number, b: number, c: any) => void;
-export const closure368_externref_shim: (a: number, b: number, c: any, d: any) => void;
+export const closure354_externref_shim: (a: number, b: number, c: any) => void;
+export const closure377_externref_shim: (a: number, b: number, c: any, d: any) => void;
 export const __wbindgen_start: () => void;