diff --git a/Cargo.lock b/Cargo.lock
index bf08894..33f018a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -367,9 +367,9 @@ checksum = "2b15c43186be67a4fd63bee50d0303afffcef381492ebe2c5d87f324e1b8815c"
 
 [[package]]
 name = "rustix"
-version = "0.38.38"
+version = "0.38.39"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "aa260229e6538e52293eeb577aabd09945a09d6d9cc0fc550ed7529056c2e32a"
+checksum = "375116bee2be9ed569afe2154ea6a99dfdffd257f533f187498c2a8f5feaf4ee"
 dependencies = [
  "bitflags",
  "errno",
@@ -436,7 +436,6 @@ dependencies = [
  "num-complex",
  "num-rational",
  "num-traits",
- "thiserror",
  "unicode-ident",
 ]
 
@@ -459,26 +458,6 @@ dependencies = [
  "talc-macros",
 ]
 
-[[package]]
-name = "thiserror"
-version = "1.0.67"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3b3c6efbfc763e64eb85c11c25320f0737cb7364c4b6336db90aa9ebe27a0bbd"
-dependencies = [
- "thiserror-impl",
-]
-
-[[package]]
-name = "thiserror-impl"
-version = "1.0.67"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b607164372e89797d78b8e23a6d67d5d1038c1c65efd52e1389ef8b77caba2a6"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn",
-]
-
 [[package]]
 name = "unicode-ident"
 version = "1.0.13"
diff --git a/Cargo.toml b/Cargo.toml
index 9144afb..dbc4fa2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -2,6 +2,11 @@
 members = ["talc-lang", "talc-bin", "talc-std", "talc-macros"]
 resolver = "2"
 
-[profile.release-lto]
+[profile.release-opt]
 inherits = "release"
 lto = "fat"
+strip = true
+codegen-units = 1
+panic = "abort"
+
+
diff --git a/talc-lang/Cargo.toml b/talc-lang/Cargo.toml
index 78ebd80..b6938ca 100644
--- a/talc-lang/Cargo.toml
+++ b/talc-lang/Cargo.toml
@@ -7,7 +7,6 @@ edition = "2021"
 num-complex = "0.4"
 num-rational = { version = "0.4", default-features = false, features = [] }
 num-traits = "0.2"
-thiserror = "1.0"
 lazy_static = "1.5"
 unicode-ident = "1.0"
 
diff --git a/talc-lang/src/chunk.rs b/talc-lang/src/chunk.rs
index 73920b2..24b55ae 100644
--- a/talc-lang/src/chunk.rs
+++ b/talc-lang/src/chunk.rs
@@ -158,10 +158,10 @@ impl std::fmt::Display for Instruction {
 	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 		match *self {
 			Self::Nop => write!(f, "nop"),
-			Self::LoadLocal(a) => write!(f, "load {}", usize::from(a)),
-			Self::StoreLocal(a) => write!(f, "store {}", usize::from(a)),
+			Self::LoadLocal(a) => write!(f, "load ${}", usize::from(a)),
+			Self::StoreLocal(a) => write!(f, "store ${}", usize::from(a)),
 			Self::NewLocal => write!(f, "newlocal"),
-			Self::DropLocal(n) => write!(f, "discardlocal {}", usize::from(n)),
+			Self::DropLocal(n) => write!(f, "discardlocal ${}", usize::from(n)),
 			Self::LoadGlobal(s) => write!(
 				f,
 				"loadglobal {}",
@@ -172,14 +172,14 @@ impl std::fmt::Display for Instruction {
 				"storeglobal {}",
 				Symbol::try_from(s).expect("symbol does not exist").name()
 			),
-			Self::CloseOver(n) => write!(f, "closeover {}", usize::from(n)),
-			Self::Closure(c) => write!(f, "closure {}", usize::from(c)),
-			Self::LoadUpvalue(n) => write!(f, "load_upval {}", usize::from(n)),
-			Self::StoreUpvalue(n) => write!(f, "store_upval {}", usize::from(n)),
-			Self::ContinueUpvalue(n) => write!(f, "cont_upval {}", usize::from(n)),
-			Self::LoadClosedLocal(n) => write!(f, "load_closed {}", usize::from(n)),
-			Self::StoreClosedLocal(n) => write!(f, "store_closed {}", usize::from(n)),
-			Self::Const(c) => write!(f, "const {}", usize::from(c)),
+			Self::CloseOver(n) => write!(f, "closeover ${}", usize::from(n)),
+			Self::Closure(c) => write!(f, "closure %{}", usize::from(c)),
+			Self::LoadUpvalue(n) => write!(f, "load_upval ^{}", usize::from(n)),
+			Self::StoreUpvalue(n) => write!(f, "store_upval ^{}", usize::from(n)),
+			Self::ContinueUpvalue(n) => write!(f, "cont_upval ^{}", usize::from(n)),
+			Self::LoadClosedLocal(n) => write!(f, "load_closed ${}", usize::from(n)),
+			Self::StoreClosedLocal(n) => write!(f, "store_closed ${}", usize::from(n)),
+			Self::Const(c) => write!(f, "const %{}", usize::from(c)),
 			Self::Int(i) => write!(f, "int {}", i64::from(i)),
 			Self::Symbol(s) => write!(
 				f,
@@ -190,24 +190,24 @@ impl std::fmt::Display for Instruction {
 			Self::Nil => write!(f, "nil"),
 			Self::Dup => write!(f, "dup"),
 			Self::DupTwo => write!(f, "duptwo"),
-			Self::Drop(n) => write!(f, "discard {}", usize::from(n)),
+			Self::Drop(n) => write!(f, "discard #{}", usize::from(n)),
 			Self::Swap => write!(f, "swap"),
 			Self::UnaryOp(o) => write!(f, "unary {o:?}"),
 			Self::BinaryOp(o) => write!(f, "binary {o:?}"),
-			Self::NewList(n) => write!(f, "newlist {n}"),
-			Self::GrowList(n) => write!(f, "growlist {n}"),
-			Self::NewTable(n) => write!(f, "newtable {n}"),
-			Self::GrowTable(n) => write!(f, "growtable {n}"),
+			Self::NewList(n) => write!(f, "newlist #{n}"),
+			Self::GrowList(n) => write!(f, "growlist #{n}"),
+			Self::NewTable(n) => write!(f, "newtable #{n}"),
+			Self::GrowTable(n) => write!(f, "growtable #{n}"),
 			Self::Index => write!(f, "index"),
 			Self::StoreIndex => write!(f, "storeindex"),
-			Self::Jump(a) => write!(f, "jump {}", usize::from(a)),
-			Self::JumpTrue(a) => write!(f, "jumptrue {}", usize::from(a)),
-			Self::JumpFalse(a) => write!(f, "jumpfalse {}", usize::from(a)),
+			Self::Jump(a) => write!(f, "jump @{}", usize::from(a)),
+			Self::JumpTrue(a) => write!(f, "jumptrue @{}", usize::from(a)),
+			Self::JumpFalse(a) => write!(f, "jumpfalse @{}", usize::from(a)),
 			Self::IterBegin => write!(f, "iterbegin"),
-			Self::IterTest(a) => write!(f, "itertest {}", usize::from(a)),
-			Self::BeginTry(t) => write!(f, "begintry {}", usize::from(t)),
+			Self::IterTest(a) => write!(f, "itertest @{}", usize::from(a)),
+			Self::BeginTry(t) => write!(f, "begintry #{}", usize::from(t)),
 			Self::EndTry => write!(f, "endtry"),
-			Self::Call(n) => write!(f, "call {n}"),
+			Self::Call(n) => write!(f, "call #{n}"),
 			Self::Return => write!(f, "return"),
 		}
 	}
diff --git a/talc-lang/src/lstring.rs b/talc-lang/src/lstring.rs
index 80325a0..9de9765 100644
--- a/talc-lang/src/lstring.rs
+++ b/talc-lang/src/lstring.rs
@@ -855,6 +855,11 @@ impl LStr {
 		self.to_str().is_ok()
 	}
 
+	#[inline]
+	pub const fn is_ascii(&self) -> bool {
+		self.as_bytes().is_ascii()
+	}
+
 	#[inline]
 	pub fn to_utf8_lossy(&self) -> Cow<'_, LStr> {
 		match String::from_utf8_lossy(self.as_bytes()) {
diff --git a/talc-lang/src/parser/lexer.rs b/talc-lang/src/parser/lexer.rs
index e1b0158..05b45d9 100644
--- a/talc-lang/src/parser/lexer.rs
+++ b/talc-lang/src/parser/lexer.rs
@@ -402,7 +402,6 @@ impl<'s> Lexer<'s> {
 			self.next()?;
 		}
 		match self.peek()? {
-			'r' => todo!("arbitrary radix integer literals"),
 			'e' => {
 				self.next()?;
 				self.next_float(true)
diff --git a/talc-lang/src/parser/util.rs b/talc-lang/src/parser/util.rs
index 1f8cb31..08cfb83 100644
--- a/talc-lang/src/parser/util.rs
+++ b/talc-lang/src/parser/util.rs
@@ -1,18 +1,18 @@
 use core::fmt;
 use std::num::{ParseFloatError, ParseIntError};
 
-use thiserror::Error;
-
 use crate::lstring::{LStr, LString};
 
 use super::Span;
 
-#[derive(Clone, Debug, Error)]
+#[derive(Clone, Debug)]
 pub struct ParserError {
 	pub span: Span,
 	pub msg: String,
 }
 
+impl std::error::Error for ParserError {}
+
 impl fmt::Display for ParserError {
 	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 		write!(f, "{} | {}", self.span, self.msg)
@@ -34,26 +34,43 @@ impl<T, E: std::error::Error> SpanParserError for Result<T, E> {
 	}
 }
 
-#[derive(Clone, Copy, Debug, Error)]
+#[derive(Clone, Copy, Debug)]
 pub enum StrEscapeError {
-	#[error("EOF in string escape")]
 	Eof,
-	#[error("EOF in string escape \\x")]
 	HexEof,
-	#[error("EOF in string escape \\u")]
 	UnicodeEof,
-	#[error("invalid string escape \\{0}")]
 	Invalid(char),
-	#[error("invalid hex digit '{0}' in string escape")]
 	InvalidHex(char),
-	#[error("missing brace after string escape \\u")]
 	MissingBrace,
-	#[error("invalid codepoint in string escape: {0:x}")]
 	InvalidCodepoint(u32),
-	#[error("codepoint in string escape too large")]
 	CodepointTooLarge,
 }
 
+impl std::error::Error for StrEscapeError {}
+
+impl fmt::Display for StrEscapeError {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		match self {
+			StrEscapeError::Eof => write!(f, "EOF in string escape"),
+			StrEscapeError::HexEof => write!(f, "EOF in string escape \\x"),
+			StrEscapeError::UnicodeEof => write!(f, "EOF in string escape \\u"),
+			StrEscapeError::Invalid(c) => write!(f, "invalid string escape \\{c}"),
+			StrEscapeError::InvalidHex(x) => {
+				write!(f, "invalid hex digit '{x}' in string escape")
+			}
+			StrEscapeError::MissingBrace => {
+				write!(f, "missing brace after string escape \\u")
+			}
+			StrEscapeError::InvalidCodepoint(n) => {
+				write!(f, "invalid codepoint in string escape: U+{n:0>4x})")
+			}
+			StrEscapeError::CodepointTooLarge => {
+				write!(f, "codepoint in string escape too large")
+			}
+		}
+	}
+}
+
 pub fn parse_str_escapes(src: &str) -> Result<LString, StrEscapeError> {
 	let mut s = LString::with_capacity(src.len());
 	let mut chars = src.chars();
diff --git a/talc-std/src/string.rs b/talc-std/src/string.rs
index 2ee25b8..4304d11 100644
--- a/talc-std/src/string.rs
+++ b/talc-std/src/string.rs
@@ -19,6 +19,7 @@ pub fn load(vm: &mut Vm) {
 	vm.set_global_name("lower", lower().into());
 	vm.set_global_name("starts_with", starts_with().into());
 	vm.set_global_name("ends_with", ends_with().into());
+	vm.set_global_name("is_ascii", is_ascii().into());
 	vm.set_global_name("is_utf8", is_utf8().into());
 	vm.set_global_name("to_utf8", to_utf8().into());
 	vm.set_global_name("to_utf8_lossy", to_utf8_lossy().into());
@@ -124,6 +125,18 @@ pub fn ends_with(_: &mut Vm, args: Vec<Value>) -> Result<Value> {
 	Ok(res.into())
 }
 
+#[native_func(1)]
+pub fn is_ascii(_: &mut Vm, args: Vec<Value>) -> Result<Value> {
+	let [_, s] = unpack_args!(args);
+	let Value::String(s) = s else {
+		throw!(
+			*SYM_TYPE_ERROR,
+			"is_ascii expected string argument, got {s:#}"
+		)
+	};
+	Ok(s.is_ascii().into())
+}
+
 #[native_func(1)]
 pub fn is_utf8(_: &mut Vm, args: Vec<Value>) -> Result<Value> {
 	let [_, s] = unpack_args!(args);