feat: Project transform

crates/iceberg/src/expr/predicate.rs

@@ -116,6 +116,9 @@ impl<T> UnaryExpression<T> {
         debug_assert!(op.is_unary());
         Self { op, term }
     }
+    pub(crate) fn op(&self) -> PredicateOperator {
+        self.op
+    }
 }
 
 /// Binary predicate, for example, `a > 10`.
@@ -144,6 +147,12 @@ impl<T> BinaryExpression<T> {
         debug_assert!(op.is_binary());
         Self { op, term, literal }
     }
+    pub(crate) fn op(&self) -> PredicateOperator {
+        self.op
+    }
+    pub(crate) fn literal(&self) -> &Datum {
+        &self.literal
+    }
 }
 
 impl<T: Display> Display for BinaryExpression<T> {
@@ -191,6 +200,12 @@ impl<T> SetExpression<T> {
         debug_assert!(op.is_set());
         Self { op, term, literals }
     }
+    pub(crate) fn op(&self) -> PredicateOperator {
+        self.op
+    }
+    pub(crate) fn literals(&self) -> &FnvHashSet<Datum> {
+        &self.literals
+    }
 }
 
 impl<T: Bind> Bind for SetExpression<T> {