Document value type

Implements #6 partially

src/value/mod.rs

@@ -5,16 +5,24 @@ mod display;
 pub type IntType = i64;
 pub type FloatType = f64;
 
+/// The value type used by the parser.
+/// Values can be of different subtypes that are the variants of this enum.
 #[derive(Clone, Debug, PartialEq)]
 pub enum Value {
+    /// A string value.
     String(String),
+    /// A float value.
     Float(FloatType),
+    /// An integer value.
     Int(IntType),
+    /// A boolean value.
     Boolean(bool),
+    /// A tuple value.
     Tuple(Vec<Value>),
 }
 
 impl Value {
+    /// Returns true if `self` is a `Value::Int`.
     pub fn is_int(&self) -> bool {
         match self {
             Value::Int(_) => true,
@@ -22,6 +30,7 @@ impl Value {
         }
     }
 
+    /// Returns true if `self` is a `Value::Float`.
     pub fn is_float(&self) -> bool {
         match self {
             Value::Float(_) => true,
@@ -29,6 +38,7 @@ impl Value {
         }
     }
 
+    /// Returns `self` as a `IntType`, or `Err` if `self` is not a `Value::Int`.
     pub fn as_int(&self) -> Result<IntType, Error> {
         match self {
             Value::Int(i) => Ok(*i),
@@ -36,6 +46,7 @@ impl Value {
         }
     }
 
+    /// Returns `self` as a `FloatType`, or `Err` if `self` is not a `Value::Float` or `Value::Int`.
     pub fn as_float(&self) -> Result<FloatType, Error> {
         match self {
             Value::Float(f) => Ok(*f),