feat: support = operator in function args (apache#1128)

Co-authored-by: Andrew Lamb <andrew@nerdnetworks.org>

Author: universalmind303

src/ast/mod.rs

@@ -4287,18 +4287,46 @@ impl fmt::Display for FunctionArgExpr {
     }
 }
 
+#[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
+/// Operator used to separate function arguments
+pub enum FunctionArgOperator {
+    /// function(arg1 = value1)
+    Equals,
+    /// function(arg1 => value1)
+    RightArrow,
+}
+
+impl fmt::Display for FunctionArgOperator {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            FunctionArgOperator::Equals => f.write_str("="),
+            FunctionArgOperator::RightArrow => f.write_str("=>"),
+        }
+    }
+}
+
 #[derive(Debug, Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 #[cfg_attr(feature = "visitor", derive(Visit, VisitMut))]
 pub enum FunctionArg {
-    Named { name: Ident, arg: FunctionArgExpr },
+    Named {
+        name: Ident,
+        arg: FunctionArgExpr,
+        operator: FunctionArgOperator,
+    },
     Unnamed(FunctionArgExpr),
 }
 
 impl fmt::Display for FunctionArg {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
-            FunctionArg::Named { name, arg } => write!(f, "{name} => {arg}"),
+            FunctionArg::Named {
+                name,
+                arg,
+                operator,
+            } => write!(f, "{name} {operator} {arg}"),
             FunctionArg::Unnamed(unnamed_arg) => write!(f, "{unnamed_arg}"),
         }
     }

src/parser/mod.rs

@@ -8106,7 +8106,22 @@ impl<'a> Parser<'a> {
             self.expect_token(&Token::RArrow)?;
             let arg = self.parse_wildcard_expr()?.into();
 
-            Ok(FunctionArg::Named { name, arg })
+            Ok(FunctionArg::Named {
+                name,
+                arg,
+                operator: FunctionArgOperator::RightArrow,
+            })
+        } else if self.peek_nth_token(1) == Token::Eq {
+            let name = self.parse_identifier(false)?;
+
+            self.expect_token(&Token::Eq)?;
+            let arg = self.parse_wildcard_expr()?.into();
+
+            Ok(FunctionArg::Named {
+                name,
+                arg,
+                operator: FunctionArgOperator::Equals,
+            })
         } else {
             Ok(FunctionArg::Unnamed(self.parse_wildcard_expr()?.into()))
         }

tests/sqlparser_common.rs

@@ -3971,12 +3971,48 @@ fn parse_named_argument_function() {
                     arg: FunctionArgExpr::Expr(Expr::Value(Value::SingleQuotedString(
                         "1".to_owned()
                     ))),
+                    operator: FunctionArgOperator::RightArrow
                 },
                 FunctionArg::Named {
                     name: Ident::new("b"),
                     arg: FunctionArgExpr::Expr(Expr::Value(Value::SingleQuotedString(
                         "2".to_owned()
                     ))),
+                    operator: FunctionArgOperator::RightArrow
+                },
+            ],
+            null_treatment: None,
+            filter: None,
+            over: None,
+            distinct: false,
+            special: false,
+            order_by: vec![],
+        }),
+        expr_from_projection(only(&select.projection))
+    );
+}
+
+#[test]
+fn parse_named_argument_function_with_eq_operator() {
+    let sql = "SELECT FUN(a = '1', b = '2') FROM foo";
+    let select = verified_only_select(sql);
+    assert_eq!(
+        &Expr::Function(Function {
+            name: ObjectName(vec![Ident::new("FUN")]),
+            args: vec![
+                FunctionArg::Named {
+                    name: Ident::new("a"),
+                    arg: FunctionArgExpr::Expr(Expr::Value(Value::SingleQuotedString(
+                        "1".to_owned()
+                    ))),
+                    operator: FunctionArgOperator::Equals
+                },
+                FunctionArg::Named {
+                    name: Ident::new("b"),
+                    arg: FunctionArgExpr::Expr(Expr::Value(Value::SingleQuotedString(
+                        "2".to_owned()
+                    ))),
+                    operator: FunctionArgOperator::Equals
                 },
             ],
             null_treatment: None,