diff --git a/implementations/rust/.gitignore b/implementations/rust/.gitignore
index 03314f7..1e7caa9 100644
--- a/implementations/rust/.gitignore
+++ b/implementations/rust/.gitignore
@@ -1 +1,2 @@
 Cargo.lock
+target/
diff --git a/implementations/rust/Makefile b/implementations/rust/Makefile
index 0b65061..b7d0767 100644
--- a/implementations/rust/Makefile
+++ b/implementations/rust/Makefile
@@ -1,2 +1,6 @@
+# cargo install cargo-watch
+watch:
+	cargo watch -x check -x 'test -- --nocapture'
+
 inotifytest:
 	inotifytest sh -c 'reset; cargo build && RUST_BACKTRACE=1 cargo test -- --nocapture'
diff --git a/implementations/rust/src/lib.rs b/implementations/rust/src/lib.rs
index b74fc75..c336852 100644
--- a/implementations/rust/src/lib.rs
+++ b/implementations/rust/src/lib.rs
@@ -94,3 +94,81 @@ mod ieee754_section_5_10_total_order_tests {
     #[test] fn case64_c3_5() { assert_eq!(d(-1e32).cmp(&d(-1e32)), Equal) }
     #[test] fn case64_c3_6() { assert_eq!(d(1e33).cmp(&d(1e33)), Equal) }
 }
+
+#[cfg(test)]
+mod value_tests {
+    use crate::value::value::Value;
+    use num::bigint::BigInt;
+
+    #[test] fn boolean_mut() {
+        let mut b = Value::Boolean(true);
+        assert!(b.is_boolean());
+        *(b.as_boolean_mut().unwrap()) = false;
+        assert_eq!(b, Value::Boolean(false));
+    }
+
+    #[test] fn float_mut() {
+        let mut f = Value::from(1.0f32);
+        assert!(f.is_float());
+        *(f.as_float_mut().unwrap()) = 123.45;
+        assert_eq!(f, Value::from(123.45f32));
+        assert_eq!(f.as_float().unwrap(), 123.45f32);
+    }
+
+    #[test] fn double_mut() {
+        let mut f = Value::from(1.0);
+        assert!(f.is_double());
+        *(f.as_double_mut().unwrap()) = 123.45;
+        assert_eq!(f, Value::from(123.45));
+        assert_eq!(f.as_double().unwrap(), 123.45);
+    }
+
+    #[test] fn signedinteger_mut() {
+        let mut i = Value::from(123);
+        assert!(i.is_signedinteger());
+        *(i.as_signedinteger_mut().unwrap()) = BigInt::from(234);
+        assert_eq!(i, Value::from(234));
+
+        use num::traits::cast::ToPrimitive;
+        assert_eq!(i.as_signedinteger().unwrap().to_i64().unwrap(), 234);
+    }
+
+    #[test] fn string_mut() {
+        let mut s = Value::from("hello, world!");
+        assert!(s.is_string());
+        s.as_string_mut().unwrap().replace_range(7..12, "there");
+        assert_eq!(s, Value::from("hello, there!"));
+    }
+
+    #[test] fn bytes_mut() {
+        let mut b = Value::from(&b"hello, world!"[..]);
+        assert!(b.is_bytestring());
+        b.as_bytestring_mut().unwrap().splice(7..12, Vec::from(&b"there"[..]));
+        assert_eq!(b, Value::from(&b"hello, there!"[..]));
+    }
+
+    #[test] fn symbol_mut() {
+        let mut s = Value::symbol("abcd");
+        assert!(s.is_symbol());
+        s.as_symbol_mut().unwrap().replace_range(..2, "AB");
+        assert_eq!(s, Value::symbol("ABcd"));
+    }
+
+    #[test] fn record_mut() {
+        let says = Value::symbol("says").wrap().rc();
+        let mut r = Value::record(&says, vec![Value::from("Tony").wrap(), Value::from("Hello!").wrap()]);
+        r.as_record_mut().unwrap().1[0] = Value::from("Alice").wrap();
+        assert_eq!(r, Value::record(&says, vec![Value::from("Alice").wrap(), Value::from("Hello!").wrap()]));
+    }
+
+    #[test] fn sequence_mut() {
+        let mut s = Value::Sequence(vec![Value::from(1).wrap(),
+                                         Value::from(2).wrap(),
+                                         Value::from(3).wrap()]);
+        let r = Value::Sequence(vec![Value::from(1).wrap(),
+                                     Value::from(99).wrap(),
+                                     Value::from(3).wrap()]);
+        s.as_sequence_mut().unwrap()[1] = Value::from(99).wrap();
+        assert_eq!(r, s);
+    }
+}
diff --git a/implementations/rust/src/value/value.rs b/implementations/rust/src/value/value.rs
index 4b6e94b..54bdc07 100644
--- a/implementations/rust/src/value/value.rs
+++ b/implementations/rust/src/value/value.rs
@@ -1,28 +1,46 @@
 use std::hash::{Hash,Hasher};
 use std::cmp::{Ordering};
 use num::bigint::BigInt;
+use std::rc::Rc;
+use std::vec::Vec;
+use std::string::String;
+use std::collections::BTreeSet;
+use std::collections::BTreeMap;
+use std::ops::Index;
+use std::ops::IndexMut;
 
+/// The `Value`s from the specification.
 #[derive(Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
 pub enum Value {
     Boolean(bool),
     Float(Float),
     Double(Double),
     SignedInteger(BigInt),
-    String(std::string::String),
-    ByteString(std::vec::Vec<u8>),
-    Symbol(std::string::String),
-    Record(std::rc::Rc<Value>, std::vec::Vec<Value>),
-    Sequence(std::vec::Vec<Value>),
-    Set(std::collections::BTreeSet<Value>),
-    Dictionary(std::collections::BTreeMap<Value, Value>),
+    String(String),
+    ByteString(Vec<u8>),
+    Symbol(String),
+    Record(Record),
+    Sequence(Vec<AValue>),
+    Set(BTreeSet<AValue>),
+    Dictionary(BTreeMap<AValue, AValue>),
 }
 
+/// An possibly-annotated Value, with annotations (themselves
+/// possibly-annotated) in order of appearance.
+#[derive(Clone, Debug)]
+pub struct AValue(Vec<AValue>, Value);
+
+/// Single-precision IEEE 754 Value
 #[derive(Clone, Debug)]
 pub struct Float(f32);
 
+/// Double-precision IEEE 754 Value
 #[derive(Clone, Debug)]
 pub struct Double(f64);
 
+/// A Record `Value`
+pub type Record = (Rc<AValue>, Vec<AValue>);
+
 impl From<f32> for Float {
     fn from(v: f32) -> Self {
         Float(v)
@@ -107,6 +125,32 @@ impl PartialOrd for Double {
 
 impl Eq for Double {}
 
+impl PartialEq for AValue {
+    fn eq(&self, other: &Self) -> bool {
+        self.1.eq(&other.1)
+    }
+}
+
+impl Eq for AValue {}
+
+impl Hash for AValue {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.1.hash(state);
+    }
+}
+
+impl PartialOrd for AValue {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+impl Ord for AValue {
+    fn cmp(&self, other: &Self) -> Ordering {
+        self.1.cmp(&other.1)
+    }
+}
+
 impl From<bool> for Value { fn from(v: bool) -> Self { Value::Boolean(v) } }
 
 impl From<f32> for Value { fn from(v: f32) -> Self { Value::Float(Float::from(v)) } }
@@ -126,3 +170,286 @@ impl From<BigInt> for Value { fn from(v: BigInt) -> Self { Value::SignedInteger(
 
 impl From<&str> for Value { fn from(v: &str) -> Self { Value::String(String::from(v)) } }
 impl From<String> for Value { fn from(v: String) -> Self { Value::String(v) } }
+
+impl From<&[u8]> for Value { fn from(v: &[u8]) -> Self { Value::ByteString(Vec::from(v)) } }
+impl From<Vec<u8>> for Value { fn from(v: Vec<u8>) -> Self { Value::ByteString(v) } }
+
+//---------------------------------------------------------------------------
+
+impl AValue {
+    pub fn rc(self) -> Rc<Self> {
+        Rc::new(self)
+    }
+
+    pub fn annotations(&self) -> &Vec<AValue> {
+        &self.0
+    }
+
+    pub fn annotations_mut(&mut self) -> &mut Vec<AValue> {
+        &mut self.0
+    }
+
+    pub fn value(&self) -> &Value {
+        &self.1
+    }
+
+    pub fn value_mut(&mut self) -> &mut Value {
+        &mut self.1
+    }
+}
+
+impl Value {
+    pub fn wrap(self) -> AValue {
+        AValue(Vec::new(), self)
+    }
+
+    pub fn is_boolean(&self) -> bool {
+        self.as_boolean().is_some()
+    }
+
+    pub fn as_boolean(&self) -> Option<bool> {
+        if let Value::Boolean(b) = *self {
+            Some(b)
+        } else {
+            None
+        }
+    }
+
+    pub fn as_boolean_mut(&mut self) -> Option<&mut bool> {
+        if let Value::Boolean(ref mut b) = *self {
+            Some(b)
+        } else {
+            None
+        }
+    }
+
+    pub fn is_float(&self) -> bool {
+        self.as_float().is_some()
+    }
+
+    pub fn as_float(&self) -> Option<f32> {
+        if let Value::Float(Float(f)) = *self {
+            Some(f)
+        } else {
+            None
+        }
+    }
+
+    pub fn as_float_mut(&mut self) -> Option<&mut f32> {
+        if let Value::Float(Float(ref mut f)) = *self {
+            Some(f)
+        } else {
+            None
+        }
+    }
+
+    pub fn is_double(&self) -> bool {
+        self.as_double().is_some()
+    }
+
+    pub fn as_double(&self) -> Option<f64> {
+        if let Value::Double(Double(f)) = *self {
+            Some(f)
+        } else {
+            None
+        }
+    }
+
+    pub fn as_double_mut(&mut self) -> Option<&mut f64> {
+        if let Value::Double(Double(ref mut f)) = *self {
+            Some(f)
+        } else {
+            None
+        }
+    }
+
+    pub fn is_signedinteger(&self) -> bool {
+        self.as_signedinteger().is_some()
+    }
+
+    pub fn as_signedinteger(&self) -> Option<&BigInt> {
+        if let Value::SignedInteger(ref i) = *self {
+            Some(i)
+        } else {
+            None
+        }
+    }
+
+    pub fn as_signedinteger_mut(&mut self) -> Option<&mut BigInt> {
+        if let Value::SignedInteger(ref mut i) = *self {
+            Some(i)
+        } else {
+            None
+        }
+    }
+
+    pub fn is_string(&self) -> bool {
+        self.as_string().is_some()
+    }
+
+    pub fn as_string(&self) -> Option<&String> {
+        if let Value::String(ref s) = *self {
+            Some(s)
+        } else {
+            None
+        }
+    }
+
+    pub fn as_string_mut(&mut self) -> Option<&mut String> {
+        if let Value::String(ref mut s) = *self {
+            Some(s)
+        } else {
+            None
+        }
+    }
+
+    pub fn is_bytestring(&self) -> bool {
+        self.as_bytestring().is_some()
+    }
+
+    pub fn as_bytestring(&self) -> Option<&Vec<u8>> {
+        if let Value::ByteString(ref s) = *self {
+            Some(s)
+        } else {
+            None
+        }
+    }
+
+    pub fn as_bytestring_mut(&mut self) -> Option<&mut Vec<u8>> {
+        if let Value::ByteString(ref mut s) = *self {
+            Some(s)
+        } else {
+            None
+        }
+    }
+
+    pub fn symbol(s: &str) -> Value {
+        Value::Symbol(s.to_string())
+    }
+
+    pub fn is_symbol(&self) -> bool {
+        self.as_symbol().is_some()
+    }
+
+    pub fn as_symbol(&self) -> Option<&String> {
+        if let Value::Symbol(ref s) = *self {
+            Some(s)
+        } else {
+            None
+        }
+    }
+
+    pub fn as_symbol_mut(&mut self) -> Option<&mut String> {
+        if let Value::Symbol(ref mut s) = *self {
+            Some(s)
+        } else {
+            None
+        }
+    }
+
+    pub fn record(label: &Rc<AValue>, fields: Vec<AValue>) -> Value {
+        Value::Record((Rc::clone(label), fields))
+    }
+
+    pub fn is_record(&self) -> bool {
+        self.as_record().is_some()
+    }
+
+    pub fn as_record(&self) -> Option<&Record> {
+        if let Value::Record(ref r) = *self {
+            Some(r)
+        } else {
+            None
+        }
+    }
+
+    pub fn as_record_mut(&mut self) -> Option<&mut Record> {
+        if let Value::Record(ref mut r) = *self {
+            Some(r)
+        } else {
+            None
+        }
+    }
+
+    pub fn is_sequence(&self) -> bool {
+        self.as_sequence().is_some()
+    }
+
+    pub fn as_sequence(&self) -> Option<&Vec<AValue>> {
+        if let Value::Sequence(ref s) = *self {
+            Some(s)
+        } else {
+            None
+        }
+    }
+
+    pub fn as_sequence_mut(&mut self) -> Option<&mut Vec<AValue>> {
+        if let Value::Sequence(ref mut s) = *self {
+            Some(s)
+        } else {
+            None
+        }
+    }
+
+    pub fn is_set(&self) -> bool {
+        self.as_set().is_some()
+    }
+
+    pub fn as_set(&self) -> Option<&BTreeSet<AValue>> {
+        if let Value::Set(ref s) = *self {
+            Some(s)
+        } else {
+            None
+        }
+    }
+
+    pub fn as_set_mut(&mut self) -> Option<&mut BTreeSet<AValue>> {
+        if let Value::Set(ref mut s) = *self {
+            Some(s)
+        } else {
+            None
+        }
+    }
+
+    pub fn is_dictionary(&self) -> bool {
+        self.as_dictionary().is_some()
+    }
+
+    pub fn as_dictionary(&self) -> Option<&BTreeMap<AValue, AValue>> {
+        if let Value::Dictionary(ref s) = *self {
+            Some(s)
+        } else {
+            None
+        }
+    }
+
+    pub fn as_dictionary_mut(&mut self) -> Option<&mut BTreeMap<AValue, AValue>> {
+        if let Value::Dictionary(ref mut s) = *self {
+            Some(s)
+        } else {
+            None
+        }
+    }
+}
+
+impl Index<usize> for Value {
+    type Output = AValue;
+
+    fn index(&self, i: usize) -> &Self::Output {
+        &self.as_sequence().unwrap()[i]
+    }
+}
+
+impl IndexMut<usize> for Value {
+    fn index_mut(&mut self, i: usize) -> &mut Self::Output {
+        &mut self.as_sequence_mut().unwrap()[i]
+    }
+}
+
+impl Index<&AValue> for Value {
+    type Output = AValue;
+
+    fn index(&self, i: &AValue) -> &Self::Output {
+        &self.as_dictionary().unwrap()[i]
+    }
+}