Fixed variable lookups and assignments

src/ast.rs

@@ -65,7 +65,12 @@ impl StmtNode {
 #[derive(Debug, Clone)]
 pub enum ExprNode {
     /// Assignment to a variable.
-    Assignment { name: Token, value: Box<ExprNode> },
+    Assignment {
+        name: Token,
+        value: Box<ExprNode>,
+        /// Identifier used for variable resolution.
+        id: usize,
+    },
 
     /// Logical binary expression.
     Logical {
@@ -94,7 +99,11 @@ pub enum ExprNode {
     Litteral { value: Token },
 
     /// A reference to a variable.
-    Variable { name: Token },
+    Variable {
+        name: Token,
+        /// Identifier used for variable resolution.
+        id: usize,
+    },
 
     /// A lambda function.
     Lambda {
@@ -227,7 +236,7 @@ impl AstDumper for StmtNode {
 impl AstDumper for ExprNode {
     fn dump(&self) -> String {
         match self {
-            Self::Assignment { name, value } => format!("( = {} {} )", name.lexeme, value.dump()),
+            Self::Assignment { name, value, id } => format!("{{#{}}}( = {} {} )", id, name.lexeme, value.dump()),
             Self::Logical {
                 left,
                 operator,
@@ -240,7 +249,7 @@ impl AstDumper for ExprNode {
             } => format!("( {} {} {} )", operator.lexeme, left.dump(), right.dump()),
             Self::Unary { operator, right } => format!("( {} {} )", operator.lexeme, right.dump()),
             Self::Grouping { expression } => format!("( {} )", expression.dump()),
-            Self::Variable { name } => name.lexeme.clone(),
+            Self::Variable { name, id } => format!("{{#{}}}{}", id, name.lexeme),
             Self::Litteral { value } => {
                 if value.is_litteral() {
                     value.lexeme.clone()
@@ -249,10 +258,7 @@ impl AstDumper for ExprNode {
                 }
             }
 
-            ExprNode::Lambda {
-                params,
-                body,
-            } => {
+            ExprNode::Lambda { params, body } => {
                 format!(
                     "( fun ({}) {} )",
                     params

src/interpreter/interpretable.rs

@@ -49,15 +49,15 @@ impl<'a> InterpreterState<'a> {
         }
     }
 
-    fn lookup_var(&self, name: &Token, expr: &ast::ExprNode) -> SloxResult<Value> {
-        match self.variables.get(&(expr as *const ast::ExprNode)) {
+    fn lookup_var(&self, name: &Token, expr_id: &usize) -> SloxResult<Value> {
+        match self.variables.get(expr_id) {
             Some(distance) => self.environment.borrow().get_at(*distance, name),
             None => self.globals.borrow().get(name),
         }
     }
 
-    fn assign_var(&self, name: &Token, expr: &ast::ExprNode, value: Value) -> SloxResult<()> {
-        match self.variables.get(&(expr as *const ast::ExprNode)) {
+    fn assign_var(&self, name: &Token, expr_id: &usize, value: Value) -> SloxResult<()> {
+        match self.variables.get(expr_id) {
             Some(distance) => self
                 .environment
                 .borrow_mut()
@@ -311,9 +311,9 @@ impl ast::StmtNode {
 impl Interpretable for ast::ExprNode {
     fn interpret(&self, es: &mut InterpreterState) -> InterpreterResult {
         match self {
-            ast::ExprNode::Assignment { name, value } => {
+            ast::ExprNode::Assignment { name, value, id } => {
                 let value = value.interpret(es)?.result();
-                es.assign_var(name, &self, value)?;
+                es.assign_var(name, id, value)?;
                 Ok(InterpreterFlowControl::default())
             }
             ast::ExprNode::Logical {
@@ -329,7 +329,7 @@ impl Interpretable for ast::ExprNode {
             ast::ExprNode::Unary { operator, right } => self.on_unary(es, operator, right),
             ast::ExprNode::Grouping { expression } => expression.interpret(es),
             ast::ExprNode::Litteral { value } => self.on_litteral(value),
-            ast::ExprNode::Variable { name } => Ok(es.lookup_var(name, &self)?.into()),
+            ast::ExprNode::Variable { name, id } => Ok(es.lookup_var(name, id)?.into()),
             ast::ExprNode::Call {
                 callee,
                 right_paren,

src/parser.rs

@@ -12,6 +12,7 @@ pub struct Parser {
     tokens: Vec<Token>,
     current: usize,
     loop_state: Vec<LoopParsingState>,
+    next_id: usize,
 }
 
 /// The state of the parser regarding loops. We may be parsing an unnamed or
@@ -69,6 +70,7 @@ impl Parser {
             tokens,
             current: 0,
             loop_state: Vec::default(),
+            next_id: 0,
         }
     }
 
@@ -511,10 +513,11 @@ impl Parser {
         let expr = self.parse_logic_or()?;
         if let Some(equals) = self.expect(&[TokenType::Equal]) {
             let value = self.parse_assignment()?;
-            if let ast::ExprNode::Variable { name } = expr {
+            if let ast::ExprNode::Variable { name, id: _ } = expr {
                 Ok(ast::ExprNode::Assignment {
                     name,
                     value: Box::new(value),
+                    id: self.make_id(),
                 })
             } else {
                 Err(SloxError::with_token(
@@ -688,6 +691,7 @@ impl Parser {
                 }),
                 TokenType::Identifier(_) => Ok(ast::ExprNode::Variable {
                     name: self.advance().clone(),
+                    id: self.make_id(),
                 }),
                 _ => self.error("expected expression"),
             }
@@ -830,4 +834,11 @@ impl Parser {
             message,
         ))
     }
+
+    /// Generate an identifier and return it.
+    fn make_id(&mut self) -> usize {
+        let id = self.next_id;
+        self.next_id += 1;
+        id
+    }
 }

src/resolver.rs

@@ -9,7 +9,7 @@ use crate::{
 /// Resolved variables. Pointers to the AST nodes using the variables are
 /// associated with the relative depth at which the variable definition will be
 /// found.
-pub type ResolvedVariables = HashMap<*const ast::ExprNode, usize>;
+pub type ResolvedVariables = HashMap<usize, usize>;
 
 /// Resolve all variables in a program's AST.
 pub fn resolve_variables(program: &ast::ProgramNode) -> SloxResult<ResolvedVariables> {
@@ -80,25 +80,29 @@ impl ResolverState {
 
     /// Try to resolve some access to a variable. If a local variable is found
     /// matching the specified name, add it to the resolution map.
-    fn resolve_local(&mut self, expr: &ast::ExprNode, name: &Token) {
+    fn resolve_local(&mut self, expr_id: &usize, name: &Token) {
         let mut i = self.scopes.len();
         while i != 0 {
             i -= 1;
             if self.scopes[i].contains_key(&name.lexeme as &str) {
-                self.mark_resolved(expr, self.scopes.len() - 1 - i);
+                self.mark_resolved(expr_id, self.scopes.len() - 1 - i);
                 return;
             }
         }
     }
 
     /// Add an entry to the resolution map for an AST node.
-    fn mark_resolved(&mut self, expr: &ast::ExprNode, depth: usize) {
-        self.resolved.insert(expr as *const ast::ExprNode, depth);
+    fn mark_resolved(&mut self, expr_id: &usize, depth: usize) {
+        self.resolved.insert(*expr_id, depth);
     }
 }
 
 /// Process a function declaration.
-fn resolve_function(rs: &mut ResolverState, params: &[Token], body: &Vec<ast::StmtNode>) -> ResolverResult {
+fn resolve_function(
+    rs: &mut ResolverState,
+    params: &[Token],
+    body: &Vec<ast::StmtNode>,
+) -> ResolverResult {
     rs.begin_scope();
     for param in params {
         rs.declare(param)?;
@@ -214,7 +218,7 @@ impl VarResolver for ast::StmtNode {
 impl VarResolver for ast::ExprNode {
     fn resolve(&self, rs: &mut ResolverState) -> ResolverResult {
         match self {
-            ast::ExprNode::Variable { name } => {
+            ast::ExprNode::Variable { name, id } => {
                 if rs.check(&name.lexeme) == Some(false) {
                     Err(SloxError::with_token(
                         ErrorKind::Parse,
@@ -222,14 +226,14 @@ impl VarResolver for ast::ExprNode {
                         "can't read local variable in its own initializer".to_owned(),
                     ))
                 } else {
-                    rs.resolve_local(self, name);
+                    rs.resolve_local(id, name);
                     Ok(())
                 }
             }
 
-            ast::ExprNode::Assignment { name, value } => {
+            ast::ExprNode::Assignment { name, value, id } => {
                 value.resolve(rs)?;
-                rs.resolve_local(self, name);
+                rs.resolve_local(id, name);
                 Ok(())
             }