better sort expr APIs

datafusion/physical-expr-common/src/sort_expr.rs

@@ -96,26 +96,34 @@ impl PhysicalSortExpr {
     }
 
     /// Set the sort sort options to ASC
-    pub fn asc(mut self) -> Self {
-        self.options.descending = false;
-        self
+    pub fn asc(self) -> Self {
+        self.with_descending(false)
     }
 
     /// Set the sort sort options to DESC
-    pub fn desc(mut self) -> Self {
-        self.options.descending = true;
-        self
+    pub fn desc(self) -> Self {
+        self.with_descending(true)
     }
 
-    /// Set the sort sort options to NULLS FIRST
-    pub fn nulls_first(mut self) -> Self {
-        self.options.nulls_first = true;
+    /// set the sort options `descending` flag
+    pub fn with_descending(mut self, descending: bool) -> Self {
+        self.options.descending = descending;
         self
     }
 
-    /// Set the sort sort options to NULLS LAST
-    pub fn nulls_last(mut self) -> Self {
-        self.options.nulls_first = false;
+    /// Set the sort options to NULLS FIRST
+    pub fn nulls_first(self) -> Self {
+        self.with_nulls_first(true)
+    }
+
+    /// Set the sort options to NULLS LAST
+    pub fn nulls_last(self) -> Self {
+        self.with_nulls_first(false)
+    }
+
+    /// set the sort options `nulls_first` flag
+    pub fn with_nulls_first(mut self, nulls_first: bool) -> Self {
+        self.options.nulls_first = nulls_first;
         self
     }
 }