Fix identifier caching; Add docs; Add minor fixes

dust-lang/src/abstract_tree.rs

@@ -155,7 +155,7 @@ impl Statement {
                 }
             },
             Statement::BuiltInFunctionCall { function, .. } => function.expected_return_type(),
-            Statement::Constant(value) => Some(value.r#type(context)),
+            Statement::Constant(value) => Some(value.r#type()),
             Statement::FunctionCall { function, .. } => function.inner.expected_type(context),
             Statement::Identifier(identifier) => context.get_type(identifier),
             Statement::If { .. } => None,

dust-lang/src/analyzer.rs

@@ -1,4 +1,4 @@
-//! Tools for analyzing an abstract syntax tree and catch errors before running the virtual
+//! Tools for analyzing an abstract syntax tree and catching errors before running the virtual
 //! machine.
 //!
 //! This module provides two anlysis options:

dust-lang/src/context.rs

@@ -40,6 +40,7 @@ impl Context {
     pub fn get_type(&self, identifier: &Identifier) -> Option<Type> {
         match self.variables.read().unwrap().get(identifier) {
             Some((VariableData::Type(r#type), _)) => Some(r#type.clone()),
+            Some((VariableData::Value(value), _)) => Some(value.r#type()),
             _ => None,
         }
     }

dust-lang/src/identifier.rs

@@ -9,11 +9,12 @@
 //! # use dust_lang::Identifier;
 //! let foo = Identifier::new("foo");
 //! let also_foo = Identifier::new("foo");
+//! let another_foo = Identifier::new("foo");
 //!
-//! assert_eq!(foo.hard_count(), 2);
+//! assert_eq!(foo.strong_count(), 4); // One for each of the above and one for the cache.
 //! ```
 use std::{
-    collections::HashSet,
+    collections::HashMap,
     fmt::{self, Display, Formatter},
     hash::Hash,
     sync::{Arc, OnceLock, RwLock},
@@ -22,11 +23,11 @@ use std::{
 use serde::{de::Visitor, Deserialize, Serialize};
 
 /// In-use identifiers.
-static IDENTIFIER_CACHE: OnceLock<RwLock<HashSet<Identifier>>> = OnceLock::new();
+static IDENTIFIER_CACHE: OnceLock<RwLock<HashMap<String, Identifier>>> = OnceLock::new();
 
 /// Returns the identifier cache.
-fn identifier_cache<'a>() -> &'a RwLock<HashSet<Identifier>> {
-    IDENTIFIER_CACHE.get_or_init(|| RwLock::new(HashSet::new()))
+fn identifier_cache<'a>() -> &'a RwLock<HashMap<String, Identifier>> {
+    IDENTIFIER_CACHE.get_or_init(|| RwLock::new(HashMap::new()))
 }
 
 /// Key used to identify a value or type.
@@ -38,25 +39,25 @@ pub struct Identifier(Arc<String>);
 impl Identifier {
     /// Creates a new identifier or returns a clone of an existing one from a cache.
     pub fn new<T: ToString>(text: T) -> Self {
-        let cache = identifier_cache().read().unwrap();
-        let new = Identifier(Arc::new(text.to_string()));
+        let string = text.to_string();
+        let mut cache = identifier_cache().write().unwrap();
 
-        if cache.contains(&new) {
-            return new;
-        }
+        if let Some(old) = cache.get(&string) {
+            old.clone()
+        } else {
+            let new = Identifier(Arc::new(string.clone()));
 
-        drop(cache);
-
-        identifier_cache().write().unwrap().insert(new.clone());
+            cache.insert(string, new.clone());
 
             new
         }
+    }
 
     pub fn as_str(&self) -> &str {
         self.0.as_str()
     }
 
-    pub fn hard_count(&self) -> usize {
+    pub fn strong_count(&self) -> usize {
         Arc::strong_count(&self.0)
     }
 }

dust-lang/src/lib.rs

@@ -25,6 +25,6 @@ pub use parser::{parse, ParseError, Parser};
 pub use r#type::Type;
 pub use token::{Token, TokenKind, TokenOwned};
 pub use value::{Value, ValueError};
-pub use vm::{run, Vm, VmError};
+pub use vm::{run, run_with_context, Vm, VmError};
 
 pub type Span = (usize, usize);

dust-lang/src/value.rs

@@ -44,10 +44,9 @@ use crate::{identifier::Identifier, AbstractSyntaxTree, Context, Type, Vm, VmErr
 /// ```
 /// # use std::collections::HashMap;
 /// # use dust_lang::*;
-/// let context = Context::new();
 /// let value = Value::integer(42);
 ///
-/// assert_eq!(value.r#type(&context), Type::Integer);
+/// assert_eq!(value.r#type(), Type::Integer);
 /// ```
 #[derive(Clone, Debug, PartialEq)]
 pub struct Value(Arc<ValueInner>);
@@ -89,8 +88,8 @@ impl Value {
         Value(Arc::new(ValueInner::String(to_string.to_string())))
     }
 
-    pub fn r#type(&self, context: &Context) -> Type {
-        self.0.r#type(context)
+    pub fn r#type(&self) -> Type {
+        self.0.r#type()
     }
 
     pub fn get_property(&self, property: &Identifier) -> Option<Value> {
@@ -665,18 +664,18 @@ pub enum ValueInner {
 }
 
 impl ValueInner {
-    fn r#type(&self, context: &Context) -> Type {
+    fn r#type(&self) -> Type {
         match self {
             ValueInner::Boolean(_) => Type::Boolean,
             ValueInner::Float(_) => Type::Float,
             ValueInner::Function(function) => Type::Function {
                 type_parameters: function.type_parameters.clone(),
                 value_parameters: function.value_parameters.clone(),
-                return_type: function.return_type(context).map(Box::new),
+                return_type: function.return_type.as_ref().cloned().map(Box::new),
             },
             ValueInner::Integer(_) => Type::Integer,
             ValueInner::List(values) => {
-                let item_type = values.first().unwrap().r#type(context);
+                let item_type = values.first().unwrap().r#type();
 
                 Type::List {
                     item_type: Box::new(item_type),
@@ -686,7 +685,7 @@ impl ValueInner {
                 let mut type_map = BTreeMap::new();
 
                 for (identifier, value) in value_map {
-                    let r#type = value.r#type(context);
+                    let r#type = value.r#type();
 
                     type_map.insert(identifier.clone(), r#type);
                 }
@@ -762,6 +761,7 @@ pub struct Function {
     pub name: Identifier,
     pub type_parameters: Option<Vec<Type>>,
     pub value_parameters: Option<Vec<(Identifier, Type)>>,
+    pub return_type: Option<Type>,
     pub body: AbstractSyntaxTree,
 }
 
@@ -786,16 +786,6 @@ impl Function {
 
         vm.run()
     }
-
-    pub fn return_type(&self, variables: &Context) -> Option<Type> {
-        self.body
-            .nodes
-            .iter()
-            .last()
-            .unwrap()
-            .inner
-            .expected_type(variables)
-    }
 }
 
 impl Display for Function {

dust-lang/src/vm.rs

@@ -15,12 +15,36 @@ use crate::{
     ValueError,
 };
 
+/// Run the source code and return the result.
+///
+/// # Example
+/// ```
+/// # use dust_lang::vm::run;
+/// # use dust_lang::value::Value;
+/// let result = run("40 + 2");
+///
+/// assert_eq!(result, Ok(Some(Value::integer(42))));
+/// ```
 pub fn run(source: &str) -> Result<Option<Value>, DustError> {
     let context = Context::new();
 
     run_with_context(source, context)
 }
 
+/// Run the source code with a context and return the result.
+///
+/// # Example
+/// ```
+/// # use dust_lang::{Context, Identifier, Value, run_with_context};
+/// let context = Context::new();
+///
+/// context.set_value(Identifier::new("foo"), Value::integer(40));
+/// context.update_last_position(&Identifier::new("foo"), (100, 100));
+///
+/// let result = run_with_context("foo + 2", context);
+///
+/// assert_eq!(result, Ok(Some(Value::integer(42))));
+/// ```
 pub fn run_with_context(source: &str, context: Context) -> Result<Option<Value>, DustError> {
     let abstract_syntax_tree = parse(source)?;
     let mut analyzer = Analyzer::new(&abstract_syntax_tree, &context);