[postgresql] Simple expression is ambiguous.

[kaby76]

Consider input SELECT 1 * 2 ^ 3 + 4;. This is parsed in two ways.

$ trparse -i 'SELECT 1 * 2 ^ 3 + 4;' --ambig | trtree -a
CSharp 0 string success 0.1303192
(root (stmtblock (stmtmulti (stmt (selectstmt (select_no_parens (select_clause (simple_select_intersect (simple_select_pramary (SELECT "SELECT") (target_list_ (target_list (target_el (a_expr (a_expr_qual (a_expr_lessless (a_expr_or (a_expr_and (a_expr_between (a_expr_in (a_expr_unary_not (a_expr_isnull (a_expr_is_not (a_expr_compare (a_expr_like (a_expr_qual_op (a_expr_unary_qualop (a_expr_add (a_expr_mul (a_expr_caret (a_expr_unary_sign (a_expr_at_time_zone (a_expr_collate (a_expr_typecast (c_expr (aexprconst (iconst (Integral "1"))))))))) (STAR "*") (a_expr_caret (a_expr_unary_sign (a_expr_at_time_zone (a_expr_collate (a_expr_typecast (c_expr (aexprconst (iconst (Integral "2")))))))) (CARET "^") (a_expr (a_expr_qual (a_expr_lessless (a_expr_or (a_expr_and (a_expr_between (a_expr_in (a_expr_unary_not (a_expr_isnull (a_expr_is_not (a_expr_compare (a_expr_like (a_expr_qual_op (a_expr_unary_qualop (a_expr_add (a_expr_mul (a_expr_caret (a_expr_unary_sign (a_expr_at_time_zone (a_expr_collate (a_expr_typecast (c_expr (aexprconst (iconst (Integral "3")))))))))) (PLUS "+") (a_expr_mul (a_expr_caret (a_expr_unary_sign (a_expr_at_time_zone (a_expr_collate (a_expr_typecast (c_expr (aexprconst (iconst (Integral "4"))))))))))))))))))))))))))))))))))))))))))))))))))) (SEMI ";"))) (EOF ""))
(root (stmtblock (stmtmulti (stmt (selectstmt (select_no_parens (select_clause (simple_select_intersect (simple_select_pramary (SELECT "SELECT") (target_list_ (target_list (target_el (a_expr (a_expr_qual (a_expr_lessless (a_expr_or (a_expr_and (a_expr_between (a_expr_in (a_expr_unary_not (a_expr_isnull (a_expr_is_not (a_expr_compare (a_expr_like (a_expr_qual_op (a_expr_unary_qualop (a_expr_add (a_expr_mul (a_expr_caret (a_expr_unary_sign (a_expr_at_time_zone (a_expr_collate (a_expr_typecast (c_expr (aexprconst (iconst (Integral "1"))))))))) (STAR "*") (a_expr_caret (a_expr_unary_sign (a_expr_at_time_zone (a_expr_collate (a_expr_typecast (c_expr (aexprconst (iconst (Integral "2")))))))) (CARET "^") (a_expr (a_expr_qual (a_expr_lessless (a_expr_or (a_expr_and (a_expr_between (a_expr_in (a_expr_unary_not (a_expr_isnull (a_expr_is_not (a_expr_compare (a_expr_like (a_expr_qual_op (a_expr_unary_qualop (a_expr_add (a_expr_mul (a_expr_caret (a_expr_unary_sign (a_expr_at_time_zone (a_expr_collate (a_expr_typecast (c_expr (aexprconst (iconst (Integral "3"))))))))))))))))))))))))))) (PLUS "+") (a_expr_mul (a_expr_caret (a_expr_unary_sign (a_expr_at_time_zone (a_expr_collate (a_expr_typecast (c_expr (aexprconst (iconst (Integral "4")))))))))))))))))))))))))))))))))) (SEMI ";"))) (EOF ""))

There should not be any ambiguity with these operators.

[kaby76]

The Floyd grammar refactoring for expressions doesn't follow the usual way you do this. I'll have to correct it.

[kaby76]

Fixed.