Method parse_with_item

crates/ruff_python_parser/src/parser/statement.rs:2465–2510

Parses a single `with` item. See:

(&mut self, state: WithItemParsingState)

    ///
    /// See: <https://docs.python.org/3/reference/compound_stmts.html#grammar-token-python-grammar-with_item>
    fn parse_with_item(&mut self, state: WithItemParsingState) -> ParsedWithItem {
        let start = self.node_start();

        // The grammar for the context expression of a with item depends on the state
        // of with item parsing.
        let context_expr = match state {
            WithItemParsingState::Speculative => {
                // If it's in a speculative state, the parenthesis (`(`) could be part of any of the
                // following expression:
                //
                // Tuple expression          -  star_named_expression
                // Generator expression      -  named_expression
                // Parenthesized expression  -  (yield_expr | named_expression)
                // Parenthesized with items  -  expression
                //
                // Here, the right side specifies the grammar for an element corresponding to the
                // expression mentioned in the left side.
                //
                // So, the grammar used should be able to parse an element belonging to any of the
                // above expression. At a later point, once the parser understands where the
                // parenthesis belongs to, it'll validate and report errors for any invalid expression
                // usage.
                //
                // Thus, we can conclude that the grammar used should be:
                //      (yield_expr | star_named_expression)
                self.parse_named_expression_or_higher(
                    ExpressionContext::yield_or_starred_bitwise_or(),
                )
            }
            WithItemParsingState::Regular => self.parse_conditional_expression_or_higher(),
        };

        let optional_vars = self
            .at(TokenKind::As)
            .then(|| Box::new(self.parse_with_item_optional_vars().expr));

        ParsedWithItem {
            is_parenthesized: context_expr.is_parenthesized,
            item: ast::WithItem {
                range: self.node_range(start),
                context_expr: context_expr.expr,
                optional_vars,
                node_index: AtomicNodeIndex::NONE,
            },
        }
    }

    /// Parses the optional variables in a `with` item.
    ///