apply cargo clippy --fix (#15)

src/context.rs

@@ -67,7 +67,7 @@ impl PyExecutionContext {
         // generate a random (unique) name for this table
         // table name cannot start with numeric digit
         let name = "c".to_owned()
-            + &Uuid::new_v4()
+            + Uuid::new_v4()
                 .to_simple()
                 .encode_lower(&mut Uuid::encode_buffer());
 

src/expression.rs

@@ -62,15 +62,15 @@ impl PyNumberProtocol for PyExpr {
     }
 
     fn __mod__(lhs: PyExpr, rhs: PyExpr) -> PyResult<PyExpr> {
-        Ok(lhs.expr.clone().modulus(rhs.expr).into())
+        Ok(lhs.expr.modulus(rhs.expr).into())
     }
 
     fn __and__(lhs: PyExpr, rhs: PyExpr) -> PyResult<PyExpr> {
-        Ok(lhs.expr.clone().and(rhs.expr).into())
+        Ok(lhs.expr.and(rhs.expr).into())
     }
 
     fn __or__(lhs: PyExpr, rhs: PyExpr) -> PyResult<PyExpr> {
-        Ok(lhs.expr.clone().or(rhs.expr).into())
+        Ok(lhs.expr.or(rhs.expr).into())
     }
 
     fn __invert__(&self) -> PyResult<PyExpr> {
@@ -140,7 +140,7 @@ impl PyMappingProtocol for PyExpr {
     fn __getitem__(&self, key: &str) -> PyResult<PyExpr> {
         Ok(Expr::GetIndexedField {
             expr: Box::new(self.expr.clone()),
-            key: ScalarValue::Utf8(Some(key.to_string()).to_owned()),
+            key: ScalarValue::Utf8(Some(key.to_string())),
         }
         .into())
     }

src/functions.rs

@@ -119,13 +119,11 @@ fn window(
         expr: datafusion::logical_plan::Expr::WindowFunction {
             fun,
             args: args.into_iter().map(|x| x.expr).collect::<Vec<_>>(),
-            partition_by: partition_by
-                .unwrap_or(vec![])
+            partition_by: partition_by.unwrap_or_default()
                 .into_iter()
                 .map(|x| x.expr)
                 .collect::<Vec<_>>(),
-            order_by: order_by
-                .unwrap_or(vec![])
+            order_by: order_by.unwrap_or_default()
                 .into_iter()
                 .map(|x| x.expr)
                 .collect::<Vec<_>>(),

src/udaf.rs

@@ -133,7 +133,7 @@ impl PyAggregateUDF {
         volatility: &str,
     ) -> PyResult<Self> {
         let function = logical_plan::create_udaf(
-            &name,
+            name,
             input_type,
             Arc::new(return_type),
             parse_volatility(volatility)?,