allow partitioning just by column

Author: JanKaul

datafusion_iceberg/src/planner.rs

@@ -440,24 +440,36 @@ impl ScalarUDFImpl for RefreshMaterializedView {
 }
 
 fn parse_transform(input: &str) -> Result<(String, Transform), Error> {
-    let re = Regex::new(r"(\w+)\((.*)\)").unwrap();
-    let caps = re
-        .captures(input)
-        .ok_or(Error::InvalidFormat("Partition transform".to_owned()))?;
-    let transform_name = caps
-        .get(1)
-        .ok_or(Error::InvalidFormat("Partition transform".to_owned()))?
-        .as_str()
-        .to_string();
-    let args = caps
-        .get(2)
-        .ok_or(Error::InvalidFormat("Partition column".to_owned()))?
-        .as_str();
-    let mut args = args.split(",").map(|s| s.to_string());
-    let column = args
-        .next()
-        .ok_or(Error::InvalidFormat("Partition column".to_owned()))?;
-    let arg = args.next();
+    let short = Regex::new(r"(\w+)").unwrap();
+    let full = Regex::new(r"(\w+)\((.*)\)").unwrap();
+
+    let (transform_name, column, arg) = if let Some(caps) = short.captures(input) {
+        let column = caps
+            .get(1)
+            .ok_or(Error::InvalidFormat("Partition column".to_owned()))?
+            .as_str()
+            .to_string();
+        ("identity".to_owned(), column, None)
+    } else {
+        let caps = full
+            .captures(input)
+            .ok_or(Error::InvalidFormat("Partition transform".to_owned()))?;
+        let transform_name = caps
+            .get(1)
+            .ok_or(Error::InvalidFormat("Partition transform".to_owned()))?
+            .as_str()
+            .to_string();
+        let args = caps
+            .get(2)
+            .ok_or(Error::InvalidFormat("Partition column".to_owned()))?
+            .as_str();
+        let mut args = args.split(",").map(|s| s.to_string());
+        let column = args
+            .next()
+            .ok_or(Error::InvalidFormat("Partition column".to_owned()))?;
+        let arg = args.next();
+        (transform_name, column, arg)
+    };
     match (transform_name.as_str(), column, arg) {
         ("identity", column, None) => Ok((column, Transform::Identity)),
         ("void", column, None) => Ok((column, Transform::Void)),