feat(df-repr): implement display for properties (#223)

Signed-off-by: Alex Chi <[email protected]>

Author: skyzh

optd-core/src/property.rs

@@ -1,5 +1,8 @@
 use crate::nodes::{ArcPredNode, NodeType};
-use std::{any::Any, fmt::Debug};
+use std::{
+    any::Any,
+    fmt::{Debug, Display},
+};
 
 pub trait PropertyBuilderAny<T: NodeType>: 'static + Send + Sync {
     fn derive_any(
@@ -13,7 +16,7 @@ pub trait PropertyBuilderAny<T: NodeType>: 'static + Send + Sync {
 }
 
 pub trait PropertyBuilder<T: NodeType>: 'static + Send + Sync + Sized {
-    type Prop: 'static + Send + Sync + Sized + Clone + Debug;
+    type Prop: 'static + Send + Sync + Sized + Clone + Debug + Display;
     fn derive(&self, typ: T, predicates: &[ArcPredNode<T>], children: &[&Self::Prop])
         -> Self::Prop;
     fn property_name(&self) -> &'static str;
@@ -41,7 +44,7 @@ impl<T: NodeType, P: PropertyBuilder<T>> PropertyBuilderAny<T> for P {
         let prop = prop
             .downcast_ref::<P::Prop>()
             .expect("Failed to downcast property");
-        format!("{:?}", prop)
+        prop.to_string()
     }
 
     fn property_name(&self) -> &'static str {

optd-datafusion-repr/src/properties/column_ref.rs

@@ -367,6 +367,26 @@ impl ColumnRefPropertyBuilder {
     }
 }
 
+impl std::fmt::Display for ColumnRef {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            ColumnRef::BaseTableColumnRef(col) => write!(f, "{}.{}", col.table, col.col_idx),
+            ColumnRef::ChildColumnRef { col_idx } => write!(f, "#{}", col_idx),
+            ColumnRef::Derived => write!(f, "Derived"),
+        }
+    }
+}
+
+impl std::fmt::Display for GroupColumnRefs {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "[{}]",
+            self.column_refs.iter().map(|x| x.to_string()).join(", ")
+        )
+    }
+}
+
 impl PropertyBuilder<DfNodeType> for ColumnRefPropertyBuilder {
     type Prop = GroupColumnRefs;
 

optd-datafusion-repr/src/properties/schema.rs

@@ -17,6 +17,16 @@ pub struct Field {
     pub nullable: bool,
 }
 
+impl std::fmt::Display for Field {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        if self.nullable {
+            write!(f, "{}:{:?}", self.name, self.typ)
+        } else {
+            write!(f, "{}:{:?}(non-null)", self.name, self.typ)
+        }
+    }
+}
+
 impl Field {
     /// Generate a field that is only a place holder whose members are never used.
     fn placeholder() -> Self {
@@ -33,6 +43,16 @@ pub struct Schema {
     pub fields: Vec<Field>,
 }
 
+impl std::fmt::Display for Schema {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "[{}]",
+            self.fields.iter().map(|x| x.to_string()).join(", ")
+        )
+    }
+}
+
 impl Schema {
     pub fn new(fields: Vec<Field>) -> Self {
         Self { fields }