feat: support function alias (#6917)

* feat: udf alias

Signed-off-by: luofucong <luofc@foxmail.com>

* trying to fix sqlness

Signed-off-by: luofucong <luofc@foxmail.com>

* x

Signed-off-by: luofucong <luofc@foxmail.com>

---------

Signed-off-by: luofucong <luofc@foxmail.com>

src/common/function/src/function.rs

@@ -70,6 +70,10 @@ pub trait Function: fmt::Display + Sync + Send {
 
     /// Evaluate the function, e.g. run/execute the function.
     fn eval(&self, ctx: &FunctionContext, columns: &[VectorRef]) -> Result<VectorRef>;
+
+    fn aliases(&self) -> &[String] {
+        &[]
+    }
 }
 
 pub type FunctionRef = Arc<dyn Function>;

src/common/function/src/function_registry.rs

@@ -64,7 +64,18 @@ impl FunctionRegistry {
 
     /// Register a scalar function in the registry.
     pub fn register_scalar(&self, func: impl Function + 'static) {
-        self.register(Arc::new(func) as FunctionRef);
+        let func = Arc::new(func) as FunctionRef;
+
+        for alias in func.aliases() {
+            let func: ScalarFunctionFactory = func.clone().into();
+            let alias = ScalarFunctionFactory {
+                name: alias.to_string(),
+                ..func
+            };
+            self.register(alias);
+        }
+
+        self.register(func)
     }
 
     /// Register an aggregate function in the registry.

src/common/function/src/scalars/ip.rs

@@ -29,7 +29,7 @@ pub(crate) struct IpFunctions;
 impl IpFunctions {
     pub fn register(registry: &FunctionRegistry) {
         // Register IPv4 functions
-        registry.register_scalar(Ipv4NumToString);
+        registry.register_scalar(Ipv4NumToString::default());
         registry.register_scalar(Ipv4StringToNum);
         registry.register_scalar(Ipv4ToCidr);
         registry.register_scalar(Ipv4InRange);

src/common/function/src/scalars/ip/ipv4.rs

@@ -34,9 +34,19 @@ use crate::function::{Function, FunctionContext};
 /// For example:
 /// - 167772160 (0x0A000000) returns "10.0.0.0"
 /// - 3232235521 (0xC0A80001) returns "192.168.0.1"
-#[derive(Clone, Debug, Default, Display)]
+#[derive(Clone, Debug, Display)]
 #[display("{}", self.name())]
-pub struct Ipv4NumToString;
+pub struct Ipv4NumToString {
+    aliases: [String; 1],
+}
+
+impl Default for Ipv4NumToString {
+    fn default() -> Self {
+        Self {
+            aliases: ["inet_ntoa".to_string()],
+        }
+    }
+}
 
 impl Function for Ipv4NumToString {
     fn name(&self) -> &str {
@@ -85,6 +95,10 @@ impl Function for Ipv4NumToString {
 
         Ok(results.to_vector())
     }
+
+    fn aliases(&self) -> &[String] {
+        &self.aliases
+    }
 }
 
 /// Function that converts a string representation of an IPv4 address to a UInt32 number.
@@ -156,7 +170,7 @@ mod tests {
 
     #[test]
     fn test_ipv4_num_to_string() {
-        let func = Ipv4NumToString;
+        let func = Ipv4NumToString::default();
         let ctx = FunctionContext::default();
 
         // Test data
@@ -193,7 +207,7 @@ mod tests {
     #[test]
     fn test_ipv4_conversions_roundtrip() {
         let to_num = Ipv4StringToNum;
-        let to_string = Ipv4NumToString;
+        let to_string = Ipv4NumToString::default();
         let ctx = FunctionContext::default();
 
         // Test data for string to num to string

src/common/function/src/scalars/udf.rs

@@ -50,6 +50,10 @@ impl ScalarUDFImpl for ScalarUdf {
         self.function.name()
     }
 
+    fn aliases(&self) -> &[String] {
+        self.function.aliases()
+    }
+
     fn signature(&self) -> &datafusion_expr::Signature {
         &self.signature
     }

src/common/function/src/system/database.rs

@@ -68,6 +68,8 @@ impl Function for DatabaseFunction {
     }
 }
 
+// Though "current_schema" can be aliased to "database", to not cause any breaking changes,
+// we are not doing it: not until https://github.com/apache/datafusion/issues/17469 is resolved.
 impl Function for CurrentSchemaFunction {
     fn name(&self) -> &str {
         CURRENT_SCHEMA_FUNCTION_NAME

tests/cases/standalone/common/function/ip.result

@@ -99,6 +99,29 @@ FROM ip_v4_data;
 | 8  | 0.0.0.0         | 0          | 0                | 0.0.0.0         |
 +----+-----------------+------------+------------------+-----------------+
 
+-- Test IPv4 string/number conversion functions, by the function alias
+-- SQLNESS SORT_RESULT 3 1
+SELECT
+    `id`,
+    ip_addr,
+    ip_numeric,
+    ipv4_string_to_num(ip_addr) AS computed_numeric,
+    inet_ntoa(ip_numeric) AS computed_addr
+FROM ip_v4_data;
+
++----+-----------------+------------+------------------+-----------------+
+| id | ip_addr         | ip_numeric | computed_numeric | computed_addr   |
++----+-----------------+------------+------------------+-----------------+
+| 1  | 192.168.1.1     | 3232235777 | 3232235777       | 192.168.1.1     |
+| 2  | 10.0.0.1        | 167772161  | 167772161        | 10.0.0.1        |
+| 3  | 172.16.0.1      | 2886729729 | 2886729729       | 172.16.0.1      |
+| 4  | 127.0.0.1       | 2130706433 | 2130706433       | 127.0.0.1       |
+| 5  | 8.8.8.8         | 134744072  | 134744072        | 8.8.8.8         |
+| 6  | 192.168.0.1     | 3232235521 | 3232235521       | 192.168.0.1     |
+| 7  | 255.255.255.255 | 4294967295 | 4294967295       | 255.255.255.255 |
+| 8  | 0.0.0.0         | 0          | 0                | 0.0.0.0         |
++----+-----------------+------------+------------------+-----------------+
+
 -- Test IPv4 CIDR functions
 -- SQLNESS SORT_RESULT 3 1
 SELECT

tests/cases/standalone/common/function/ip.sql

@@ -74,6 +74,16 @@ SELECT
     ipv4_num_to_string(ip_numeric) AS computed_addr
 FROM ip_v4_data;
 
+-- Test IPv4 string/number conversion functions, by the function alias
+-- SQLNESS SORT_RESULT 3 1
+SELECT
+    `id`,
+    ip_addr,
+    ip_numeric,
+    ipv4_string_to_num(ip_addr) AS computed_numeric,
+    inet_ntoa(ip_numeric) AS computed_addr
+FROM ip_v4_data;
+
 -- Test IPv4 CIDR functions
 -- SQLNESS SORT_RESULT 3 1
 SELECT