diff --git a/examples/io.lysp b/examples/io.lysp
new file mode 100644
index 0000000..5bb5bf2
--- /dev/null
+++ b/examples/io.lysp
@@ -0,0 +1,5 @@
+;; vi:ft=lisp:sw=2:ts=2
+
+(let (f (fopen (car *args*)))
+  (fwrite (fread f))
+  )
diff --git a/src/compile/block.rs b/src/compile/block.rs
index 56d956d..b493ddd 100644
--- a/src/compile/block.rs
+++ b/src/compile/block.rs
@@ -9,7 +9,7 @@ use crate::{
         syntax::{
             CallExpression, CondExpression, DefmacroExpression, DefunExpression, Expression,
             FunctionBody, IfExpression, LambdaExpression, LetExpression, LoopExpression,
-            PrognExpression, SetqExpression, WhileExpression,
+            PrognExpression, SetqExpression, VectorExpression, WhileExpression,
         },
         value::{BuiltinFunction, CompileConstant, CompileValue},
     },
@@ -625,6 +625,23 @@ impl<'a> LocalBlock<'a> {
         Ok(CompileValue::Nil)
     }
 
+    fn compile_vector(
+        &mut self,
+        vector: &VectorExpression,
+        break_label: Option<u32>,
+    ) -> Result<CompileValue, CompileError> {
+        for expression in vector.elements.iter().rev() {
+            let value = self.compile_expression(expression, break_label)?;
+            self.compile_push(value)?;
+        }
+        self.compile_push(CompileValue::Global("vector".into()))?;
+        let Some(count) = U::new(vector.elements.len() as u32) else {
+            todo!()
+        };
+        self.function.emit(Instruction::Call(count));
+        Ok(CompileValue::Stack)
+    }
+
     pub fn compile_expression(
         &mut self,
         expression: &Rc<Expression>,
@@ -638,6 +655,7 @@ impl<'a> LocalBlock<'a> {
             Expression::Identifier(identifier) => self.compile_identifier(identifier),
             Expression::Lambda(lambda) => self.compile_lambda(lambda),
             Expression::Defun(defun) => self.compile_defun(defun),
+            Expression::Vector(vector) => self.compile_vector(vector, break_label),
             Expression::Call(call) => self.compile_call(call, break_label),
             Expression::If(condition) => self.compile_if(condition, break_label),
             Expression::Cond(condition) => self.compile_cond(condition, break_label),
diff --git a/src/compile/syntax/mod.rs b/src/compile/syntax/mod.rs
index 8d31b33..a8b03ea 100644
--- a/src/compile/syntax/mod.rs
+++ b/src/compile/syntax/mod.rs
@@ -10,6 +10,7 @@ mod function;
 mod lambda;
 mod loops;
 mod macros;
+mod vector;
 
 pub use binding::*;
 pub use call::*;
@@ -19,6 +20,7 @@ pub use function::*;
 pub use lambda::*;
 pub use loops::*;
 pub use macros::*;
+pub use vector::*;
 
 #[derive(Debug, PartialEq)]
 pub enum Expression {
@@ -40,6 +42,7 @@ pub enum Expression {
     While(WhileExpression),
     Loop(LoopExpression),
     Progn(PrognExpression),
+    Vector(VectorExpression),
     Return,
 }
 
@@ -67,7 +70,6 @@ impl Expression {
             Value::Boolean(value) => Rc::new(Self::BooleanLiteral(*value)),
             Value::Integer(value) => Rc::new(Self::IntegerLiteral(*value)),
             Value::String(value) => Rc::new(Self::StringLiteral(value.clone())),
-            Value::Vector(_vector) => todo!(),
             Value::Identifier(value) => Rc::new(Self::Identifier(value.clone())),
             Value::Quasi(_value) => todo!("{value}"),
             Value::Unquote(_value) => todo!("Unquote {_value}"),
@@ -116,6 +118,9 @@ impl Expression {
                     _ => Self::map_or(CallExpression::parse(cons, value), Expression::Call),
                 }
             }
+            Value::Vector(vector) => {
+                Rc::new(Self::Vector(VectorExpression::parse(&vector.borrow())))
+            }
             Value::Keyword(_) => todo!(),
             Value::NativeFunction(_) | Value::BytecodeFunction(_) | Value::OpaqueValue(_) => {
                 todo!()
@@ -142,6 +147,7 @@ impl CollectErrors<ParseError> for Expression {
             Self::While(cloop) => cloop.collect_errors(errors),
             Self::Loop(cloop) => cloop.collect_errors(errors),
             Self::Progn(progn) => progn.collect_errors(errors),
+            Self::Vector(vector) => vector.collect_errors(errors),
             Self::Nil
             | Self::Return
             | Self::IntegerLiteral(_)
diff --git a/src/compile/syntax/vector.rs b/src/compile/syntax/vector.rs
new file mode 100644
index 0000000..ed61f50
--- /dev/null
+++ b/src/compile/syntax/vector.rs
@@ -0,0 +1,29 @@
+use std::rc::Rc;
+
+use crate::{
+    compile::{Expression, ParseError, syntax::CollectErrors},
+    vm::value::Value,
+};
+
+#[derive(Debug, PartialEq)]
+pub struct VectorExpression {
+    pub elements: Vec<Rc<Expression>>,
+}
+
+impl VectorExpression {
+    pub fn parse(values: &[Value]) -> Self {
+        Self {
+            elements: values.iter().map(Expression::parse_inner).collect(),
+        }
+    }
+}
+
+impl CollectErrors<ParseError> for VectorExpression {
+    fn collect_errors(&self, errors: &mut Vec<ParseError>) -> bool {
+        let mut r = false;
+        for expr in self.elements.iter() {
+            r |= expr.collect_errors(errors);
+        }
+        r
+    }
+}
diff --git a/src/parse.rs b/src/parse.rs
index bf8e527..4226720 100644
--- a/src/parse.rs
+++ b/src/parse.rs
@@ -14,7 +14,7 @@ use nom::{
     sequence::{delimited, preceded},
 };
 
-use crate::vm::value::{Keyword, Value};
+use crate::vm::value::{Keyword, Value, Vector};
 
 struct IdentifierHead;
 struct IdentifierTail;
@@ -179,6 +179,17 @@ fn parse_list_or_nil(input: &str) -> IResult<&str, Value> {
     .parse(input)
 }
 
+fn parse_vector(input: &str) -> IResult<&str, Value> {
+    delimited(
+        char('['),
+        many0(preceded(skip_comment_and_whitespace, parse_value)),
+        preceded(skip_comment_and_whitespace, char(']')),
+    )
+    .map(Vector::from)
+    .map(Value::from)
+    .parse(input)
+}
+
 fn parse_boolean(input: &str) -> IResult<&str, Value> {
     map(
         alt((
@@ -298,6 +309,7 @@ fn parse_quote(input: &str) -> IResult<&str, Value> {
 pub fn parse_value(input: &str) -> IResult<&str, Value> {
     alt((
         parse_list_or_nil,
+        parse_vector,
         parse_boolean,
         parse_quote,
         parse_quasi,
diff --git a/src/vm/macros.rs b/src/vm/macros.rs
index c7fa0c8..70d7849 100644
--- a/src/vm/macros.rs
+++ b/src/vm/macros.rs
@@ -75,7 +75,11 @@ impl MacroExpand for Value {
                 let value = expand_quasiquote(value);
                 value.macro_expand(vm, env, false)
             }
-            Self::Vector(_) => todo!(),
+            Self::Vector(vector) => Ok(Value::Vector(
+                vector
+                    .try_map(|value| value.macro_expand(vm, env, false))?
+                    .into(),
+            )),
         }
     }
 }
diff --git a/src/vm/prelude/io.rs b/src/vm/prelude/io.rs
new file mode 100644
index 0000000..f4d360c
--- /dev/null
+++ b/src/vm/prelude/io.rs
@@ -0,0 +1,119 @@
+use std::{
+    cell::RefCell,
+    fs::File,
+    io::{Read, Write, stdin, stdout},
+};
+
+use crate::vm::{
+    env::Environment,
+    value::{Value, Vector},
+};
+
+enum FileStream {
+    Closed,
+    File(File),
+}
+
+enum Stream {
+    Stdin,
+    Stdout,
+    File(RefCell<FileStream>),
+}
+
+impl Stream {
+    fn read_bytes(&self, data: &mut [u8]) -> Option<usize> {
+        let result = match self {
+            Self::Stdin => stdin().read(data),
+            Self::Stdout => return None,
+            Self::File(file) => match &mut *file.borrow_mut() {
+                FileStream::File(file) => file.read(data),
+                FileStream::Closed => return None,
+            },
+        };
+        result.ok()
+    }
+
+    fn write_bytes(&self, data: &[u8]) -> Option<usize> {
+        match self {
+            Self::Stdin => None,
+            Self::Stdout => stdout().write(data).ok(),
+            Self::File(file) => match &mut *file.borrow_mut() {
+                FileStream::File(file) => file.write(data).ok(),
+                FileStream::Closed => None,
+            },
+        }
+    }
+}
+
+pub(super) fn load(env: &mut Environment) {
+    env.set_global_value("*stdin*", Value::opaque(Stream::Stdin));
+    env.set_global_value("*stdout*", Value::opaque(Stream::Stdout));
+
+    env.defun_native("fopen", |_, _, args| {
+        let [path] = args else {
+            todo!();
+        };
+        let Value::String(path) = path else { todo!() };
+        match File::open(&**path) {
+            Ok(file) => Ok(Value::opaque(Stream::File(RefCell::new(FileStream::File(
+                file,
+            ))))),
+            Err(_) => Ok(Value::Nil),
+        }
+    });
+    env.defun_native("fclose", |vm, _, args| {
+        let [stream] = args else { todo!() };
+        let stream = stream
+            .as_opaque::<Stream>()
+            .map_err(|e| vm.error_at_ip(e))?;
+        if let Stream::File(file) = stream {
+            *file.borrow_mut() = FileStream::Closed;
+        }
+        Ok(Value::Nil)
+    });
+    env.defun_native("fread", |vm, _, args| {
+        let stream = match args {
+            [] => &Stream::Stdin,
+            [stream] => stream
+                .as_opaque::<Stream>()
+                .map_err(|e| vm.error_at_ip(e))?,
+            _ => todo!(),
+        };
+        let mut buffer = [0; 256];
+        let count = stream.read_bytes(&mut buffer);
+        match count {
+            Some(len) => {
+                let vector = Vector::from_iter(&buffer[..len]);
+                Ok(Value::Vector(vector.into()))
+            }
+            None => Ok(Value::Nil),
+        }
+    });
+    env.defun_native("fwrite", |vm, _, args| {
+        let (stream, data) = match args {
+            [data] => (&Stream::Stdout, data),
+            [stream, data] => (
+                stream
+                    .as_opaque::<Stream>()
+                    .map_err(|e| vm.error_at_ip(e))?,
+                data,
+            ),
+            _ => todo!(),
+        };
+
+        match data {
+            Value::Vector(vector) => {
+                let bytes = vector.to_bytes().unwrap();
+                match stream.write_bytes(&bytes) {
+                    Some(count) => Ok(Value::Integer(count as i64)),
+                    None => Ok(Value::Nil),
+                }
+            }
+            Value::String(value) => match stream.write_bytes(value.as_bytes()) {
+                Some(count) => Ok(Value::Integer(count as i64)),
+                None => Ok(Value::Nil),
+            },
+            _ => todo!(),
+        }
+    });
+}
diff --git a/src/vm/prelude/math.rs b/src/vm/prelude/math.rs
index b3822ff..c1acda0 100644
--- a/src/vm/prelude/math.rs
+++ b/src/vm/prelude/math.rs
@@ -267,3 +267,25 @@ pub(crate) fn builtin_cmp_le(
 ) -> Result<Value, MachineError> {
     builtin_cmp(vm, args, CompareOperation::Le)
 }
+
+pub(super) fn load(env: &mut Environment) {
+    // math
+    env.defun_native("+", builtin_add);
+    env.defun_native("-", builtin_sub);
+    env.defun_native("*", builtin_mul);
+    env.defun_native("%", builtin_mod);
+    env.defun_native("/", builtin_div);
+
+    env.defun_native("&&", builtin_and);
+    env.defun_native("||", builtin_or);
+    env.defun_native("&", builtin_bitwise_and);
+    env.defun_native("|", builtin_bitwise_or);
+    env.defun_native("^", builtin_bitwise_xor);
+
+    env.defun_native(">", builtin_cmp_gt);
+    env.defun_native("<", builtin_cmp_lt);
+    env.defun_native("=", builtin_cmp_eq);
+    env.defun_native("/=", builtin_cmp_ne);
+    env.defun_native(">=", builtin_cmp_ge);
+    env.defun_native("<=", builtin_cmp_le);
+}
diff --git a/src/vm/prelude/mod.rs b/src/vm/prelude/mod.rs
index f68faa7..e02a667 100644
--- a/src/vm/prelude/mod.rs
+++ b/src/vm/prelude/mod.rs
@@ -6,33 +6,18 @@ use crate::{
     util::IteratorExt,
     vm::{
         env::Environment,
-        value::{AnyFunction, ConsCell, Keyword, TryFromValue, Value, ValueString},
+        value::{AnyFunction, ConsCell, Keyword, TryFromValue, Value, ValueString, Vector},
     },
 };
 
+mod io;
 mod math;
+
 pub(crate) use math::*;
 
 pub fn load(env: &mut Environment) {
-    // math
-    env.defun_native("+", builtin_add);
-    env.defun_native("-", builtin_sub);
-    env.defun_native("*", builtin_mul);
-    env.defun_native("%", builtin_mod);
-    env.defun_native("/", builtin_div);
-
-    env.defun_native("&&", builtin_and);
-    env.defun_native("||", builtin_or);
-    env.defun_native("&", builtin_bitwise_and);
-    env.defun_native("|", builtin_bitwise_or);
-    env.defun_native("^", builtin_bitwise_xor);
-
-    env.defun_native(">", builtin_cmp_gt);
-    env.defun_native("<", builtin_cmp_lt);
-    env.defun_native("=", builtin_cmp_eq);
-    env.defun_native("/=", builtin_cmp_ne);
-    env.defun_native(">=", builtin_cmp_ge);
-    env.defun_native("<=", builtin_cmp_le);
+    math::load(env);
+    io::load(env);
 
     // conversion
     env.defun_native("string->int", |vm, _, args| {
@@ -51,6 +36,10 @@ pub fn load(env: &mut Environment) {
         let result = Value::String(format!("{arg}").into());
         Ok(result)
     });
+    env.defun_native("vector", |_, _, args| {
+        let vector = Vector::from_iter(args.iter().cloned());
+        Ok(Value::Vector(vector.into()))
+    });
 
     // lists
     env.defun_native("car", |vm, _env, args| {
diff --git a/src/vm/value/convert.rs b/src/vm/value/convert.rs
index f570626..7bb1fbf 100644
--- a/src/vm/value/convert.rs
+++ b/src/vm/value/convert.rs
@@ -39,6 +39,12 @@ macro_rules! impl_primitive_value {
                 }
             }
 
+            impl From<&$t> for Value {
+                fn from(value: &$t) -> Self {
+                    Self::Integer(*value as i64)
+                }
+            }
+
             impl TryFromValue<'_> for $t {
                 fn try_from_value(value: &Value) -> Result<Self, MachineErrorKind> {
                     match value {
diff --git a/src/vm/value/mod.rs b/src/vm/value/mod.rs
index 6978e8d..eb93a92 100644
--- a/src/vm/value/mod.rs
+++ b/src/vm/value/mod.rs
@@ -1,4 +1,4 @@
-use std::{fmt, hash::Hash, rc::Rc};
+use std::{any::Any, fmt, hash::Hash, rc::Rc};
 
 use crate::{
     compile::{ExpectedWhat, ExpectedWhere, ParseError, ParseErrorKind},
@@ -78,6 +78,12 @@ impl Value {
         matches!(self, Self::Nil)
     }
 
+    pub fn opaque<T: 'static>(value: T) -> Self {
+        let value: Rc<dyn Any> = Rc::new(value);
+        let opaque = OpaqueValue::from(value);
+        Self::OpaqueValue(opaque)
+    }
+
     pub fn as_opaque<T: 'static>(&self) -> Result<&T, MachineErrorKind> {
         match self {
             Self::OpaqueValue(opaque) => opaque.cast(),
@@ -135,6 +141,12 @@ impl Value {
     }
 }
 
+impl From<Vector> for Value {
+    fn from(value: Vector) -> Self {
+        Self::Vector(Rc::new(value))
+    }
+}
+
 impl fmt::Display for Value {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
diff --git a/src/vm/value/vector.rs b/src/vm/value/vector.rs
index fc3de68..2c2e41a 100644
--- a/src/vm/value/vector.rs
+++ b/src/vm/value/vector.rs
@@ -5,7 +5,10 @@ use std::{
     ops::Deref,
 };
 
-use crate::vm::value::Value;
+use crate::{
+    error::MachineErrorKind,
+    vm::value::{TryFromValue, Value},
+};
 
 #[derive(Debug, PartialEq, Eq)]
 pub struct Vector(RefCell<Vec<Value>>);
@@ -16,7 +19,21 @@ impl Hash for Vector {
     }
 }
 
+impl From<Vec<Value>> for Vector {
+    fn from(value: Vec<Value>) -> Self {
+        Self(RefCell::new(value))
+    }
+}
+
 impl Vector {
+    pub fn try_map<E, F: FnMut(&Value) -> Result<Value, E>>(&self, map: F) -> Result<Vector, E> {
+        self.0.borrow().iter().map(map).collect()
+    }
+
+    pub fn to_bytes(&self) -> Result<Vec<u8>, MachineErrorKind> {
+        self.0.borrow().iter().map(u8::try_from_value).collect()
+    }
+
     pub fn is_empty(&self) -> bool {
         self.0.borrow().is_empty()
     }
@@ -26,9 +43,17 @@ impl Vector {
     }
 }
 
-impl FromIterator<Value> for Vector {
-    fn from_iter<T: IntoIterator<Item = Value>>(iter: T) -> Self {
-        Self(RefCell::new(Vec::from_iter(iter)))
+// impl FromIterator<Value> for Vector {
+//     fn from_iter<T: IntoIterator<Item = Value>>(iter: T) -> Self {
+//         Self(RefCell::new(Vec::from_iter(iter)))
+//     }
+// }
+
+impl<T: Into<Value>> FromIterator<T> for Vector {
+    fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Self {
+        Self(RefCell::new(Vec::from_iter(
+            iter.into_iter().map(Into::into),
+        )))
     }
 }