Add ?? break/continue/return/throw.

CHANGELOG.md

@@ -17,6 +17,7 @@ Bug fixes
 New features
 ------------
 
+* The `break`, `continue`, `return` and `throw` statements can now follow the `??` operator to short-circuit operations where the value is `()`.
 * A new symbol, `$func$`, is added to custom syntax to allow parsing of anonymous functions.
 
 

src/parser.rs

@@ -2265,20 +2265,31 @@ impl Engine {
 
             // Parse the RHS
             let rhs = match op_token {
+                Token::DoubleQuestion
+                    if matches!(
+                        state.input.peek().unwrap().0,
+                        Token::Break | Token::Continue | Token::Return | Token::Throw
+                    ) =>
+                {
+                    let stmt = self.parse_stmt(state, settings)?;
+                    let block: StmtBlock = stmt.into();
+                    Expr::Stmt(block.into())
+                }
                 // [xxx..] | (xxx..) | {xxx..} | xxx.., | xxx..; | xxx.. =>
                 // [xxx..=] | (xxx..=) | {xxx..=} | xxx..=, | xxx..=; | xxx..= =>
-                Token::ExclusiveRange | Token::InclusiveRange => {
-                    let (next_op, next_pos) = state.input.peek().unwrap();
-
-                    match next_op {
+                Token::ExclusiveRange | Token::InclusiveRange
+                    if matches!(
+                        state.input.peek().unwrap().0,
                         Token::RightBracket
-                        | Token::RightParen
-                        | Token::RightBrace
-                        | Token::Comma
-                        | Token::SemiColon
-                        | Token::DoubleArrow => Expr::Unit(*next_pos),
-                        _ => self.parse_unary(state, settings)?,
-                    }
+                            | Token::RightParen
+                            | Token::RightBrace
+                            | Token::Comma
+                            | Token::SemiColon
+                            | Token::DoubleArrow
+                    ) =>
+                {
+                    let (_, next_pos) = state.input.peek().unwrap();
+                    Expr::Unit(*next_pos)
                 }
                 _ => self.parse_unary(state, settings)?,
             };

tests/looping.rs

@@ -28,6 +28,20 @@ fn test_loop() {
         21
     );
 
+    assert_eq!(
+        engine
+            .eval::<INT>(
+                "
+                    for n in 0..10 {
+                        let x = if n <= 5 { n };
+                        x ?? break 42;
+                    }
+                "
+            )
+            .unwrap(),
+        42
+    );
+
     assert_eq!(*engine.compile("let x = 0; break;").unwrap_err().err_type(), ParseErrorType::LoopBreak);
 
     #[cfg(not(feature = "no_function"))]