* Working proof of concept for breaking with labels

boa/src/exec/iteration/mod.rs

@@ -36,8 +36,17 @@ impl Executable for ForLoop {
             let result = self.body().run(interpreter)?;
 
             match interpreter.get_current_state() {
-                InterpreterState::Break(_label) => {
-                    // TODO break to label.
+                InterpreterState::Break(label) => {
+                    // If a label is set we want to break the current block and still keep state as Break if the label is a block above
+                    if let Some(stmt_label) = &self.label {
+                        if let Some(brk_label) = label {
+                            // We have a label, but not for the current statement
+                            // break without resetting to executing
+                            if stmt_label != brk_label {
+                                break;
+                            }
+                        }
+                    }
 
                     // Loops 'consume' breaks.
                     interpreter.set_current_state(InterpreterState::Executing);

boa/src/syntax/ast/node/iteration.rs

@@ -21,11 +21,18 @@ use serde::{Deserialize, Serialize};
 pub struct ForLoop {
     #[cfg_attr(feature = "serde", serde(flatten))]
     inner: Box<InnerForLoop>,
+    pub label: Option<String>,
 }
 
 impl ForLoop {
     /// Creates a new for loop AST node.
-    pub(in crate::syntax) fn new<I, C, E, B>(init: I, condition: C, final_expr: E, body: B) -> Self
+    pub(in crate::syntax) fn new<I, C, E, B>(
+        init: I,
+        condition: C,
+        final_expr: E,
+        body: B,
+        label: Option<String>,
+    ) -> Self
     where
         I: Into<Option<Node>>,
         C: Into<Option<Node>>,
@@ -34,6 +41,7 @@ impl ForLoop {
     {
         Self {
             inner: Box::new(InnerForLoop::new(init, condition, final_expr, body)),
+            label,
         }
     }
 

boa/src/syntax/parser/statement/iteration/for_statement.rs

@@ -31,11 +31,12 @@ use crate::{
 ///
 /// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for
 /// [spec]: https://tc39.es/ecma262/#sec-for-statement
-#[derive(Debug, Clone, Copy)]
+#[derive(Debug, Clone)]
 pub(in crate::syntax::parser::statement) struct ForStatement {
     allow_yield: AllowYield,
     allow_await: AllowAwait,
     allow_return: AllowReturn,
+    label: Option<String>,
 }
 
 impl ForStatement {
@@ -44,6 +45,7 @@ impl ForStatement {
         allow_yield: Y,
         allow_await: A,
         allow_return: R,
+        label: Option<String>,
     ) -> Self
     where
         Y: Into<AllowYield>,
@@ -54,6 +56,7 @@ impl ForStatement {
             allow_yield: allow_yield.into(),
             allow_await: allow_await.into(),
             allow_return: allow_return.into(),
+            label,
         }
     }
 }
@@ -104,6 +107,6 @@ impl TokenParser for ForStatement {
             Statement::new(self.allow_yield, self.allow_await, self.allow_return).parse(cursor)?;
 
         // TODO: do not encapsulate the `for` in a block just to have an inner scope.
-        Ok(ForLoop::new(init, cond, step, body))
+        Ok(ForLoop::new(init, cond, step, body, self.label))
     }
 }

boa/src/syntax/parser/statement/labelled_stm/mod.rs

@@ -39,12 +39,12 @@ impl Label {
 }
 
 impl TokenParser for Label {
-    type Output = Box<str>;
+    type Output = String;
 
     fn parse(self, cursor: &mut Cursor<'_>) -> Result<Self::Output, ParseError> {
         let _timer = BoaProfiler::global().start_event("Label", "Parsing");
         let name = LabelIdentifier::new(self.allow_yield, self.allow_await).parse(cursor)?;
         cursor.expect(Punctuator::Colon, "Labelled Statement")?;
-        Ok(name)
+        Ok(name.to_string())
     }
 }

boa/src/syntax/parser/statement/mod.rs

@@ -99,6 +99,7 @@ impl TokenParser for Statement {
         // TODO: add BreakableStatement and divide Whiles, fors and so on to another place.
         let mut tok = cursor.peek(0).ok_or(ParseError::AbruptEnd)?;
 
+        // Is this statement prefixed with a label?
         let label =
             Label::new(self.allow_yield, self.allow_await, self.allow_return).try_parse(cursor);
 
@@ -128,7 +129,7 @@ impl TokenParser for Statement {
                     .map(Node::from)
             }
             TokenKind::Keyword(Keyword::For) => {
-                ForStatement::new(self.allow_yield, self.allow_await, self.allow_return)
+                ForStatement::new(self.allow_yield, self.allow_await, self.allow_return, label)
                     .parse(cursor)
                     .map(Node::from)
             }