1use crate::{2 create_error, future_wrapper, map::LayeredHashMap, rc_fn_helper, resolved_lazy_val, Error,3 LazyBinding, LazyVal, ObjValue, Result, Val,4};5use std::{6 cell::RefCell,7 collections::HashMap,8 fmt::Debug,9 rc::{Rc, Weak},10};1112rc_fn_helper!(13 ContextCreator,14 context_creator,15 dyn Fn(Option<ObjValue>, Option<ObjValue>) -> Result<Context>16);1718future_wrapper!(Context, FutureContext);1920struct ContextInternals {21 dollar: Option<ObjValue>,22 this: Option<ObjValue>,23 super_obj: Option<ObjValue>,24 bindings: LayeredHashMap<Rc<str>, LazyVal>,25}26impl Debug for ContextInternals {27 fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {28 f.debug_struct("Context")29 .field("this", &self.this.as_ref().map(|e| Rc::as_ptr(&e.0)))30 .field("bindings", &self.bindings)31 .finish()32 }33}3435#[derive(Debug, Clone)]36pub struct Context(Rc<ContextInternals>);37impl Context {38 pub fn new_future() -> FutureContext {39 FutureContext(Rc::new(RefCell::new(None)))40 }4142 pub fn dollar(&self) -> &Option<ObjValue> {43 &self.0.dollar44 }4546 pub fn this(&self) -> &Option<ObjValue> {47 &self.0.this48 }4950 pub fn super_obj(&self) -> &Option<ObjValue> {51 &self.0.super_obj52 }5354 pub fn new() -> Context {55 Context(Rc::new(ContextInternals {56 dollar: None,57 this: None,58 super_obj: None,59 bindings: LayeredHashMap::default(),60 }))61 }6263 pub fn binding(&self, name: Rc<str>) -> Result<LazyVal> {64 self.065 .bindings66 .get(&name)67 .cloned()68 .ok_or_else(|| create_error(Error::UnknownVariable(name)))69 }70 pub fn into_future(self, ctx: FutureContext) -> Context {71 {72 ctx.0.borrow_mut().replace(self);73 }74 ctx.unwrap()75 }7677 pub fn with_var(&self, name: Rc<str>, value: Val) -> Result<Context> {78 let mut new_bindings = HashMap::with_capacity(1);79 new_bindings.insert(name, resolved_lazy_val!(value));80 self.extend(new_bindings, None, None, None)81 }8283 pub fn extend(84 &self,85 new_bindings: HashMap<Rc<str>, LazyVal>,86 new_dollar: Option<ObjValue>,87 new_this: Option<ObjValue>,88 new_super_obj: Option<ObjValue>,89 ) -> Result<Context> {90 let dollar = new_dollar.or_else(|| self.0.dollar.clone());91 let this = new_this.or_else(|| self.0.this.clone());92 let super_obj = new_super_obj.or_else(|| self.0.super_obj.clone());93 let bindings = if new_bindings.is_empty() {94 self.0.bindings.clone()95 } else {96 self.0.bindings.extend(new_bindings)97 };98 Ok(Context(Rc::new(ContextInternals {99 dollar,100 this,101 super_obj,102 bindings,103 })))104 }105 pub fn extend_unbound(106 &self,107 new_bindings: HashMap<Rc<str>, LazyBinding>,108 new_dollar: Option<ObjValue>,109 new_this: Option<ObjValue>,110 new_super_obj: Option<ObjValue>,111 ) -> Result<Context> {112 let this = new_this.or_else(|| self.0.this.clone());113 let super_obj = new_super_obj.or_else(|| self.0.super_obj.clone());114 let mut new = HashMap::with_capacity(new_bindings.len());115 for (k, v) in new_bindings.into_iter() {116 new.insert(k, v.evaluate(this.clone(), super_obj.clone())?);117 }118 self.extend(new, new_dollar, this, super_obj)119 }120 pub fn into_weak(self) -> WeakContext {121 WeakContext(Rc::downgrade(&self.0))122 }123}124125impl Default for Context {126 fn default() -> Self {127 Self::new()128 }129}130131impl PartialEq for Context {132 fn eq(&self, other: &Self) -> bool {133 Rc::ptr_eq(&self.0, &other.0)134 }135}136137#[derive(Debug, Clone)]138pub struct WeakContext(Weak<ContextInternals>);139impl WeakContext {140 pub fn upgrade(&self) -> Context {141 Context(self.0.upgrade().expect("context is removed"))142 }143}144impl PartialEq for WeakContext {145 fn eq(&self, other: &Self) -> bool {146 self.0.ptr_eq(&other.0)147 }148}