From 16151bd3262d549859b0e8ed3d6a31c0cca21423 Mon Sep 17 00:00:00 2001
From: Emmanuel Benoit <tseeker@nocternity.net>
Date: Tue, 10 Jan 2023 09:03:57 +0100
Subject: [PATCH] Actually made "this" work in the interpreter
---
src/interpreter/classes.rs | 85 ++++------------------------------
src/interpreter/environment.rs | 5 ++
src/interpreter/functions.rs | 15 ++++--
src/interpreter/value.rs | 11 +----
4 files changed, 27 insertions(+), 89 deletions(-)
diff --git a/src/interpreter/classes.rs b/src/interpreter/classes.rs
index acf0a70..bde5c2d 100644
--- a/src/interpreter/classes.rs
+++ b/src/interpreter/classes.rs
@@ -1,16 +1,12 @@
-use std::{
- cell::RefCell,
- collections::HashMap,
- fmt::Display,
- rc::Rc,
-};
+use std::{cell::RefCell, collections::HashMap, fmt::Display, rc::Rc};
use crate::{
errors::{ErrorKind, SloxError, SloxResult},
+ interpreter::EnvironmentRef,
tokens::{Token, TokenType},
};
-use super::{functions::Function, Callable, InterpreterState, Value};
+use super::{functions::Function, Callable, Environment, InterpreterState, Value};
/// A Lox class.
#[derive(Debug, Clone)]
@@ -86,11 +82,8 @@ impl Instance {
if let Some(value) = self.fields.get(&name.lexeme) {
return Ok(value.clone());
}
- if self.class.borrow().methods.get(&name.lexeme).is_some() {
- let bound_method = BoundMethod {
- instance: this_value.clone(),
- method: name.lexeme.clone(),
- };
+ if let Some(method) = self.class.borrow().methods.get(&name.lexeme) {
+ let bound_method = self.bind_method(method, this_value);
return Ok(Value::from(bound_method));
}
@@ -105,16 +98,10 @@ impl Instance {
self.fields.insert(name.lexeme.clone(), value);
}
- fn with_method<F, Rt>(&self, name: &str, f: F) -> Rt
- where
- F: FnOnce(&Function) -> Rt,
- {
- let cls = self.class.borrow();
- let method = cls
- .methods
- .get(name)
- .expect(&format!("Method {} not found", name));
- f(method)
+ fn bind_method(&self, method: &Function, this_value: &Value) -> Function {
+ let bm = method.copy_with_child_env();
+ bm.env().set("this", this_value.clone());
+ bm
}
}
@@ -123,57 +110,3 @@ impl Display for Instance {
f.write_fmt(format_args!("<Instance of {}>", self.class.borrow(),))
}
}
-
-/* --------------------------- *
- * Bound method implementation *
- * --------------------------- */
-
-impl BoundMethod {
- fn with_method<F, Rt>(&self, f: F) -> Rt
- where
- F: FnOnce(&Function) -> Rt,
- {
- self.instance.with_instance(
- |instance| instance.with_method(&self.method, f),
- || panic!("Instance value does not contain an instance"),
- )
- }
-
- fn this_token(&self) -> Token {
- Token {
- token_type: TokenType::This,
- lexeme: "this".to_owned(),
- line: self.with_method(|method| method.name().expect("Method has no name").line),
- }
- }
-}
-
-impl Callable for BoundMethod {
- fn arity(&self) -> usize {
- self.with_method(|m| m.arity())
- }
-
- fn call(&self, itpr_state: &mut InterpreterState, arguments: Vec<Value>) -> SloxResult<Value> {
- let mut this_env = InterpreterState::create_child(itpr_state);
- this_env
- .environment
- .borrow_mut()
- .define(&self.this_token(), Some(self.instance.clone()))?;
- println!("{:?}", this_env.locals);
- self.with_method(|m| m.call(&mut this_env, arguments))
- }
-}
-
-impl Display for BoundMethod {
- fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
- self.instance.with_instance(
- |instance| {
- f.write_fmt(format_args!(
- "<Bound method {} of {}>",
- self.method, instance
- ))
- },
- || panic!("Instance value does not contain an instance"),
- )
- }
-}
diff --git a/src/interpreter/environment.rs b/src/interpreter/environment.rs
index c8dbce2..b493d46 100644
--- a/src/interpreter/environment.rs
+++ b/src/interpreter/environment.rs
@@ -117,6 +117,11 @@ impl Environment {
}
}
+ /// Set a variable in an environment, directly, without any checks.
+ pub fn set(&mut self, name: &str, value: Value) {
+ self.values.insert(name.to_owned(), Some(value));
+ }
+
/// Read an ancestor from the chain of enclosing environments.
fn ancestor(&self, distance: usize) -> EnvironmentRef {
let mut ancestor = self.enclosing.clone().expect("ancestor() called at root");
diff --git a/src/interpreter/functions.rs b/src/interpreter/functions.rs
index 1813719..23d98e2 100644
--- a/src/interpreter/functions.rs
+++ b/src/interpreter/functions.rs
@@ -1,4 +1,4 @@
-use std::fmt::Display;
+use std::{fmt::Display, cell::RefMut};
use itertools::izip;
@@ -32,8 +32,17 @@ impl Function {
}
}
- pub(super) fn name(&self) -> Option<&Token> {
- self.name.as_ref()
+ pub(super) fn copy_with_child_env(&self) -> Self {
+ Self {
+ name: self.name.clone(),
+ params: self.params.clone(),
+ body: self.body.clone(),
+ env: Environment::create_child(&self.env),
+ }
+ }
+
+ pub(super) fn env(&self) -> RefMut<Environment> {
+ self.env.borrow_mut()
}
}
diff --git a/src/interpreter/value.rs b/src/interpreter/value.rs
index 0de565a..7f1b8cd 100644
--- a/src/interpreter/value.rs
+++ b/src/interpreter/value.rs
@@ -1,7 +1,7 @@
use std::{cell::RefCell, fmt::Display, rc::Rc};
use super::{
- classes::{Class, ClassRef, Instance, BoundMethod},
+ classes::{Class, ClassRef, Instance},
functions::Function,
native_fn::NativeFunction,
Callable,
@@ -23,7 +23,6 @@ pub enum Object {
LoxFunction(Function),
Class(ClassRef),
Instance(Instance),
- BoundMethod(BoundMethod),
}
/* -------------------- *
@@ -57,7 +56,6 @@ impl Value {
Object::LoxFunction(func) => fok(func),
Object::Class(class) => fok(class),
Object::Instance(_) => ferr(),
- Object::BoundMethod(bm) => fok(bm),
}
}
@@ -150,12 +148,6 @@ impl From<Instance> for Value {
}
}
-impl From<BoundMethod> for Value {
- fn from(value: BoundMethod) -> Self {
- Value::Object(Rc::new(RefCell::new(Object::BoundMethod(value))))
- }
-}
-
/* --------------------- *
* Object implementation *
* --------------------- */
@@ -167,7 +159,6 @@ impl Display for Object {
Object::LoxFunction(func) => func.fmt(f),
Object::Class(cls) => cls.borrow().fmt(f),
Object::Instance(inst) => inst.fmt(f),
- Object::BoundMethod(bm) => bm.fmt(f),
}
}
}