json_object('k' VALUE 'v') in postgres

Fixes apache#1545

Author: lovasoa

src/ast/mod.rs

@@ -5462,6 +5462,8 @@ pub enum FunctionArgOperator {
     Assignment,
     /// function(arg1 : value1)
     Colon,
+    /// function(arg1 VALUE value1)
+    Value,
 }
 
 impl fmt::Display for FunctionArgOperator {
@@ -5471,6 +5473,7 @@ impl fmt::Display for FunctionArgOperator {
             FunctionArgOperator::RightArrow => f.write_str("=>"),
             FunctionArgOperator::Assignment => f.write_str(":="),
             FunctionArgOperator::Colon => f.write_str(":"),
+            FunctionArgOperator::Value => f.write_str("VALUE"),
         }
     }
 }

src/parser/mod.rs

@@ -11411,6 +11411,7 @@ impl<'a> Parser<'a> {
             Token::Colon if self.dialect.supports_named_fn_args_with_colon_operator() => {
                 Ok(FunctionArgOperator::Colon)
             }
+            Token::Word(w) if w.value.to_uppercase() == "VALUE" => Ok(FunctionArgOperator::Value),
             _ => {
                 self.prev_token();
                 self.expected("argument operator", tok)

tests/sqlparser_postgres.rs

@@ -2812,6 +2812,19 @@ fn test_json() {
     );
 }
 
+#[test]
+fn test_json_object() {
+    match pg().verified_expr("JSON_OBJECT('name' VALUE 'value')") {
+        Expr::Function(Function { args: FunctionArguments::List(FunctionArgumentList { args, .. }), .. }) => {
+            assert!(matches!(
+                &args[..],
+                &[FunctionArg::ExprNamed { operator: FunctionArgOperator::Value, .. }]
+            ));
+        }
+        other => panic!("Expected: JSON_OBJECT('name' VALUE 'value') to be parsed as a function, but got {other:?}"),
+    }
+}
+
 #[test]
 fn parse_json_table_is_not_reserved() {
     // JSON_TABLE is not a reserved keyword in PostgreSQL, even though it is in SQL:2023