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use crate::{
builtins::iterable::get_iterator,
environment::{
declarative_environment_record::DeclarativeEnvironmentRecord,
lexical_environment::VariableScope,
},
exec::{Executable, InterpreterState},
gc::{Finalize, Trace},
syntax::ast::node::{Declaration, Node},
BoaProfiler, Context, JsResult, JsValue,
};
use std::fmt;
#[cfg(feature = "deser")]
use serde::{Deserialize, Serialize};
#[cfg_attr(feature = "deser", derive(Serialize, Deserialize))]
#[derive(Clone, Debug, Trace, Finalize, PartialEq)]
pub struct ForOfLoop {
variable: Box<Node>,
iterable: Box<Node>,
body: Box<Node>,
label: Option<Box<str>>,
}
impl ForOfLoop {
pub fn new<V, I, B>(variable: V, iterable: I, body: B) -> Self
where
V: Into<Node>,
I: Into<Node>,
B: Into<Node>,
{
Self {
variable: Box::new(variable.into()),
iterable: Box::new(iterable.into()),
body: Box::new(body.into()),
label: None,
}
}
pub fn variable(&self) -> &Node {
&self.variable
}
pub fn iterable(&self) -> &Node {
&self.iterable
}
pub fn body(&self) -> &Node {
&self.body
}
pub fn label(&self) -> Option<&str> {
self.label.as_ref().map(Box::as_ref)
}
pub fn set_label(&mut self, label: Box<str>) {
self.label = Some(label);
}
pub fn display(&self, f: &mut fmt::Formatter<'_>, indentation: usize) -> fmt::Result {
if let Some(ref label) = self.label {
write!(f, "{}: ", label)?;
}
write!(f, "for ({} of {}) ", self.variable, self.iterable)?;
self.body().display(f, indentation)
}
}
impl fmt::Display for ForOfLoop {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.display(f, 0)
}
}
impl From<ForOfLoop> for Node {
fn from(for_of: ForOfLoop) -> Node {
Self::ForOfLoop(for_of)
}
}
impl Executable for ForOfLoop {
fn run(&self, context: &mut Context) -> JsResult<JsValue> {
let _timer = BoaProfiler::global().start_event("ForOf", "exec");
let iterable = self.iterable().run(context)?;
let iterator = get_iterator(&iterable, context)?;
let mut result = JsValue::undefined();
loop {
{
let env = context.get_current_environment();
context.push_environment(DeclarativeEnvironmentRecord::new(Some(env)));
}
let iterator_result = iterator.next(context)?;
if iterator_result.done {
context.pop_environment();
break;
}
let next_result = iterator_result.value;
match self.variable() {
Node::Identifier(ref name) => {
if context.has_binding(name.as_ref())? {
// Binding already exists
context.set_mutable_binding(
name.as_ref(),
next_result.clone(),
context.strict(),
)?;
} else {
context.create_mutable_binding(
name.as_ref(),
true,
VariableScope::Function,
)?;
context.initialize_binding(name.as_ref(), next_result)?;
}
}
Node::VarDeclList(ref list) => match list.as_ref() {
[var] => {
if var.init().is_some() {
return context.throw_syntax_error("a declaration in the head of a for-of loop can't have an initializer");
}
match &var {
Declaration::Identifier { ident, .. } => {
if context.has_binding(ident.as_ref())? {
context.set_mutable_binding(
ident.as_ref(),
next_result,
context.strict(),
)?;
} else {
context.create_mutable_binding(
ident.as_ref(),
false,
VariableScope::Function,
)?;
context.initialize_binding(ident.as_ref(), next_result)?;
}
}
Declaration::Pattern(p) => {
for (ident, value) in p.run(Some(next_result), context)? {
if context.has_binding(ident.as_ref())? {
context.set_mutable_binding(
ident.as_ref(),
value,
context.strict(),
)?;
} else {
context.create_mutable_binding(
ident.as_ref(),
false,
VariableScope::Function,
)?;
context.initialize_binding(ident.as_ref(), value)?;
}
}
}
}
}
_ => {
return context.throw_syntax_error(
"only one variable can be declared in the head of a for-of loop",
)
}
},
Node::LetDeclList(ref list) => match list.as_ref() {
[var] => {
if var.init().is_some() {
return context.throw_syntax_error("a declaration in the head of a for-of loop can't have an initializer");
}
match &var {
Declaration::Identifier { ident, .. } => {
context.create_mutable_binding(
ident.as_ref(),
false,
VariableScope::Block,
)?;
context.initialize_binding(ident.as_ref(), next_result)?;
}
Declaration::Pattern(p) => {
for (ident, value) in p.run(Some(next_result), context)? {
context.create_mutable_binding(
ident.as_ref(),
false,
VariableScope::Block,
)?;
context.initialize_binding(ident.as_ref(), value)?;
}
}
}
}
_ => {
return context.throw_syntax_error(
"only one variable can be declared in the head of a for-of loop",
)
}
},
Node::ConstDeclList(ref list) => match list.as_ref() {
[var] => {
if var.init().is_some() {
return context.throw_syntax_error("a declaration in the head of a for-of loop can't have an initializer");
}
match &var {
Declaration::Identifier { ident, .. } => {
context.create_immutable_binding(
ident.as_ref(),
false,
VariableScope::Block,
)?;
context.initialize_binding(ident.as_ref(), next_result)?;
}
Declaration::Pattern(p) => {
for (ident, value) in p.run(Some(next_result), context)? {
context.create_immutable_binding(
ident.as_ref(),
false,
VariableScope::Block,
)?;
context.initialize_binding(ident.as_ref(), value)?;
}
}
}
}
_ => {
return context.throw_syntax_error(
"only one variable can be declared in the head of a for-of loop",
)
}
},
Node::Assign(_) => {
return context.throw_syntax_error(
"a declaration in the head of a for-of loop can't have an initializer",
);
}
_ => {
return context
.throw_syntax_error("unknown left hand side in head of for-of loop")
}
}
result = self.body().run(context)?;
match context.executor().get_current_state() {
InterpreterState::Break(label) => {
handle_state_with_labels!(self, label, context, break);
break;
}
InterpreterState::Continue(label) => {
handle_state_with_labels!(self, label, context, continue);
}
InterpreterState::Return => return Ok(result),
InterpreterState::Executing => {
// Continue execution.
}
}
let _ = context.pop_environment();
}
Ok(result)
}
}