final version with Arc<Mutex<Object>>

src/executor.rs

@@ -5,7 +5,7 @@ use std::collections::HashMap;
 use std::fmt::Display;
 use std::error::Error;
 use std::io;
-use std::sync::Arc;
+use std::sync::{Arc, Mutex};
 use std::cell::RefCell;
 
 #[derive(Debug)]
@@ -51,15 +51,15 @@ where
     I: Iterator<Item = Result<ParseTree, ParseError>>
 {
     exprs: &'a mut I,
-    globals: &'a mut HashMap<String, Arc<RefCell<Object>>>,
+    globals: &'a mut HashMap<String, Arc<Mutex<Object>>>,
-    locals: HashMap<String, Arc<RefCell<Object>>>,
+    locals: HashMap<String, Arc<Mutex<Object>>>,
 }
 
 impl<'a, I> Executor<'a, I>
 where
     I: Iterator<Item = Result<ParseTree, ParseError>>,
 {
-    pub fn new(exprs: &'a mut I, globals: &'a mut HashMap<String, Arc<RefCell<Object>>>) -> Self {
+    pub fn new(exprs: &'a mut I, globals: &'a mut HashMap<String, Arc<Mutex<Object>>>) -> Self {
         Self {
             exprs,
             globals,
@@ -67,27 +67,27 @@ where
         }
     }
 
-    pub fn _add_global(self, k: String, v: Arc<RefCell<Object>>) -> Self {
+    pub fn _add_global(self, k: String, v: Arc<Mutex<Object>>) -> Self {
         self.globals.insert(k, v);
         self
     }
 
-    pub fn locals(mut self, locals: HashMap<String, Arc<RefCell<Object>>>) -> Self {
+    pub fn locals(mut self, locals: HashMap<String, Arc<Mutex<Object>>>) -> Self {
         self.locals = locals;
         self
     }
 
-    pub fn add_local(mut self, k: String, v: Arc<RefCell<Object>>) -> Self {
+    pub fn add_local(mut self, k: String, v: Arc<Mutex<Object>>) -> Self {
         self.locals.insert(k, v);
         self
     }
 
-    fn _get_object(&self, ident: &String) -> Result<&Arc<RefCell<Object>>, RuntimeError> {
+    fn _get_object(&self, ident: &String) -> Result<&Arc<Mutex<Object>>, RuntimeError> {
         self.locals.get(ident).or(self.globals.get(ident))
             .ok_or(RuntimeError::VariableUndefined(ident.clone()))
     }
 
-    fn get_object_mut(&mut self, ident: &String) -> Result<&mut Arc<RefCell<Object>>, RuntimeError> {
+    fn get_object_mut(&mut self, ident: &String) -> Result<&mut Arc<Mutex<Object>>, RuntimeError> {
         self.locals.get_mut(ident).or(self.globals.get_mut(ident))
             .ok_or(RuntimeError::VariableUndefined(ident.clone()))
     }
@@ -96,6 +96,30 @@ where
         self.locals.contains_key(ident) || self.globals.contains_key(ident)
     }
 
+    fn eval(obj: &mut Arc<Mutex<Object>>) -> Result<Value, RuntimeError> {
+        let mut guard = obj.lock().unwrap();
+
+        let v = guard.eval()?;
+
+        Ok(v)
+    }
+
+    fn obj_locals(obj: &Arc<Mutex<Object>>) -> HashMap<String, Arc<Mutex<Object>>> {
+        let guard = obj.lock().unwrap();
+
+        let locals = guard.locals();
+
+        locals
+    }
+
+    fn obj_globals(obj: &Arc<Mutex<Object>>) -> HashMap<String, Arc<Mutex<Object>>> {
+        let guard = obj.lock().unwrap();
+
+        let locals = guard.globals();
+
+        locals
+    }
+
     pub fn exec(&mut self, tree: Box<ParseTree>) -> Result<Value, RuntimeError> {
         match *tree {
             ParseTree::Add(x, y) => match (self.exec(x)?, self.exec(y)?) {
@@ -238,7 +262,7 @@ where
 
                     Executor::new(self.exprs, &mut self.globals)
                         .locals(self.locals.clone())
-                        .add_local(ident, Arc::new(RefCell::new(Object::value(value, g, self.locals.to_owned()))))
+                        .add_local(ident, Arc::new(Mutex::new(Object::value(value, g, self.locals.to_owned()))))
                         .exec(scope)
                 }
             },
@@ -249,7 +273,7 @@ where
                     let g = self.globals.clone();
                     Executor::new(self.exprs, &mut self.globals)
                         .locals(self.locals.clone())
-                        .add_local(ident, Arc::new(RefCell::new(Object::variable(*body, g, self.locals.to_owned()))))
+                        .add_local(ident, Arc::new(Mutex::new(Object::variable(*body, g, self.locals.to_owned()))))
                         .exec(scope)
                 }
             },
@@ -257,7 +281,7 @@ where
                 let g = self.globals.clone();
                 Executor::new(self.exprs, &mut self.globals)
                     .locals(self.locals.clone())
-                    .add_local(func.name().unwrap().to_string(), Arc::new(RefCell::new(Object::function(func, g, self.locals.clone()))))
+                    .add_local(func.name().unwrap().to_string(), Arc::new(Mutex::new(Object::function(func, g, self.locals.clone()))))
                     .exec(scope)
             },
             ParseTree::Compose(x, y) => {
@@ -294,17 +318,17 @@ where
             ParseTree::FunctionCall(ident, args) => {
                 let args = args.into_iter().map(|x| Object::variable(x, self.globals.clone(), self.locals.clone())).collect();
                 let obj = self.get_object_mut(&ident)?;
-                let v = obj.borrow_mut().eval()?;
+                let v = Self::eval(obj)?;
 
                 match v {
-                    Value::Function(mut f) => f.call(obj.borrow().globals(), obj.borrow().locals(), args),
+                    Value::Function(mut f) => f.call(Self::obj_globals(obj), Self::obj_locals(obj), args),
                     _ => Err(RuntimeError::FunctionUndefined(ident.clone()))
                 }
             },
             ParseTree::Variable(ident) => {
                 let obj = self.get_object_mut(&ident)?;
 
-                let v = obj.borrow_mut().eval()?;
+                let v = obj.lock().unwrap().eval()?;
 
                 Ok(v)
             },
@@ -352,7 +376,7 @@ where
             ParseTree::NonCall(name) => {
                 let obj = self.get_object_mut(&name)?;
 
-                let v = obj.borrow_mut().eval()?;
+                let v = obj.lock().unwrap().eval()?;
 
                 Ok(v)
             }

src/function.rs

@@ -5,7 +5,7 @@ use crate::{Type, Object, Value};
 
 use std::collections::HashMap;
 use std::fmt::{self, Display};
-use std::sync::Arc;
+use std::sync::{Arc, Mutex};
 
 #[derive(Clone, Debug, PartialEq)]
 pub struct FunctionType(pub Box<Type>, pub Vec<Type>);
@@ -52,8 +52,8 @@ impl Function {
 	}
 
 	pub(crate) fn call(&mut self,
-                mut globals: HashMap<String, Arc<RefCell<Object>>>,
+                mut globals: HashMap<String, Arc<Mutex<Object>>>,
-                locals: HashMap<String, Arc<RefCell<Object>>>,
+                locals: HashMap<String, Arc<Mutex<Object>>>,
                 args: Vec<Object>) -> Result<Value, RuntimeError>
     {
         let mut tree = vec![Ok(*self.body.clone())].into_iter();
@@ -63,11 +63,11 @@ impl Function {
             .locals(locals.clone());
 
         for (obj, name) in std::iter::zip(args.into_iter(), self.arg_names.clone().into_iter()) {
-            exec = exec.add_local(name.clone(), Arc::new(RefCell::new(obj)));
+            exec = exec.add_local(name.clone(), Arc::new(Mutex::new(obj)));
         }
 
         if let Some(name) = self.name().map(|x| x.to_string()) {
-            exec = exec.add_local(name, Arc::new(RefCell::new(Object::function(self.clone(), g, locals))));
+            exec = exec.add_local(name, Arc::new(Mutex::new(Object::function(self.clone(), g, locals))));
         }
 
         exec.next().unwrap()

src/lib.rs

@@ -13,7 +13,7 @@ use std::fmt::Display;
 use std::io::BufRead;
 use std::fmt;
 use std::iter::Peekable;
-use std::sync::Arc;
+use std::sync::{Arc, Mutex};
 use std::cell::RefCell;
 
 #[derive(Clone, Debug)]
@@ -101,15 +101,21 @@ enum Cache {
     Uncached(ParseTree),
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug)]
 struct Object {
-    locals: HashMap<String, Arc<RefCell<Object>>>,
+    locals: HashMap<String, Arc<Mutex<Object>>>,
-    globals: HashMap<String, Arc<RefCell<Object>>>,
+    globals: HashMap<String, Arc<Mutex<Object>>>,
     value: Cache,
 }
 
+impl PartialEq for Object {
+    fn eq(&self, other: &Self) -> bool {
+        self.value == other.value
+    }
+}
+
 impl Object {
-    pub fn variable(tree: ParseTree, globals: HashMap<String, Arc<RefCell<Object>>>, locals: HashMap<String, Arc<RefCell<Object>>>) -> Self {
+    pub fn variable(tree: ParseTree, globals: HashMap<String, Arc<Mutex<Object>>>, locals: HashMap<String, Arc<Mutex<Object>>>) -> Self {
         Self {
             locals,
             globals,
@@ -117,7 +123,7 @@ impl Object {
         }
     }
 
-    pub fn value(v: Value, globals: HashMap<String, Arc<RefCell<Object>>>, locals: HashMap<String, Arc<RefCell<Object>>>) -> Self {
+    pub fn value(v: Value, globals: HashMap<String, Arc<Mutex<Object>>>, locals: HashMap<String, Arc<Mutex<Object>>>) -> Self {
         Self {
             locals,
             globals,
@@ -125,7 +131,7 @@ impl Object {
         }
     }
 
-    pub fn function(func: Function, globals: HashMap<String, Arc<RefCell<Object>>>, locals: HashMap<String, Arc<RefCell<Object>>>) -> Self {
+    pub fn function(func: Function, globals: HashMap<String, Arc<Mutex<Object>>>, locals: HashMap<String, Arc<Mutex<Object>>>) -> Self {
         Self {
             locals,
             globals,
@@ -152,11 +158,11 @@ impl Object {
         }
     }
 
-    pub fn locals(&self) -> HashMap<String, Arc<RefCell<Object>>> {
+    pub fn locals(&self) -> HashMap<String, Arc<Mutex<Object>>> {
         self.locals.clone()
     }
 
-    pub fn globals(&self) -> HashMap<String, Arc<RefCell<Object>>> {
+    pub fn globals(&self) -> HashMap<String, Arc<Mutex<Object>>> {
         self.globals.clone()
     }
 }
@@ -164,7 +170,7 @@ impl Object {
 pub struct Runtime<'a, R: BufRead> {
     tokenizer: Peekable<Tokenizer<R>>,
     global_types: HashMap<String, Type>,
-    globals: HashMap<String, Arc<RefCell<Object>>>,
+    globals: HashMap<String, Arc<Mutex<Object>>>,
     parser: Option<Parser<'a, Tokenizer<R>>>,
 }