parser: handle chained array indexing in parse_place and add tests

parser/src/pratt.rs

@@ -382,15 +382,30 @@ impl<'a, 'b> Pratt<'a, 'b> {
             }
             tok if tok.is_place() => {
                 let expr = self.parse_lhs(lex, 0)?;
-                if lex.consume(&Token::OpenBracket) {
+                if lex.peek_is(&Token::OpenBracket) {
                     let Expr::Leaf(Atom::Variable(var)) = expr else {
                         return Err(ParsingError::OperatorExpectsVariable(start..lex.span().end));
                     };
-                    let expr =
-                        self.parse_expression(lex, ArrayOperator::Index.binding_power().1)?;
-                    let index = self.parse_comma_expr(lex, expr)?;
-                    lex.expect(&Token::ClosedBracket, ParsingError::UnclosedArrayAccess)?;
-                    return Ok(Place::Index(var, index));
+
+                    let index = self.parse_index_exprs(lex, ArrayOperator::Index)?;
+
+                    if !lex.peek_is(&Token::OpenBracket) {
+                        return Ok(Place::Index(var, index));
+                    }
+
+                    let mut lhs = Expr::node(
+                        ExprNode::ArrayOperation(ArrayOperator::Index, var, index),
+                        self.parser.arena,
+                    );
+
+                    while lex.peek_is(&Token::OpenBracket) {
+                        let index = self.parse_index_exprs(lex, ArrayOperator::Index)?;
+                        if lex.peek_is(&Token::OpenBracket) {
+                            lhs = Expr::node(ExprNode::NestedArray(lhs, index), self.parser.arena);
+                        } else {
+                            return Ok(Place::ChainedIndex(lhs, index));
+                        }
+                    }
                 }
                 expr
             }

parser/src/tests.rs

@@ -282,6 +282,46 @@ fn test_parser_arrays() {
     ));
 }
 
+#[test]
+fn test_parser_nested_arrays() {
+    let source = "
+        { a[1][2] }
+        { a[1][2][3] }
+        { a[1][2] = 2 }
+        { a[1][2][3] = 2 }
+        { a[1][2][3][4][5] = 2 }
+        { ++a[1][2] }
+        { a[1][2]-- }
+        { a[1][2] += 1 }
+        { b = a[1][2] }
+        { b = a[1][2][3] }
+        { a[1, 2][3] }
+        { a[1][2, 3] }
+    ";
+    test_parser!(source => {
+        rules: [
+            (None, Some("(body (Index (Index awk::a 1) 2))")),
+            (None, Some("(body (Index (Index (Index awk::a 1) 2) 3))")),
+            (None, Some("(body (Assignment (Index (Index awk::a 1) 2) 2))")),
+            (None, Some("(body (Assignment (Index (Index (Index awk::a 1) 2) 3) 2))")),
+            (None, Some("(body (Assignment (Index (Index (Index (Index (Index awk::a 1) 2) 3) 4) 5) 2))")),
+            (None, Some("(body (IncrementL (Index (Index awk::a 1) 2)))")),
+            (None, Some("(body (DecrementR (Index (Index awk::a 1) 2)))")),
+            (None, Some("(body (AddAssign (Index (Index awk::a 1) 2) 1))")),
+            (None, Some("(body (Assignment awk::b (Index (Index awk::a 1) 2)))")),
+            (None, Some("(body (Assignment awk::b (Index (Index (Index awk::a 1) 2) 3)))")),
+            (None, Some("(body (Index (Index awk::a 1 2) 3))")),
+            (None, Some("(body (Index (Index awk::a 1) 2 3))")),
+        ],
+    });
+
+    test_parser!(is_err!(
+        "{ 2[1][2] }",
+        "{ \"a\"[1][2] }",
+        "{ (a + b)[1][2] }"
+    ));
+}
+
 #[test]
 fn test_parser_for_loop() {
     let source = "