add field_path!() macro

Signed-off-by: Andrew Duffy <[email protected]>

Author: a10y

vortex-dtype/src/field.rs

@@ -91,6 +91,21 @@ impl Display for Field {
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct FieldPath(Vec<Field>);
 
+/// A helpful constructor for creating `FieldPath`s to nested
+/// struct fields of the format `field_path!(x.y.z)`
+#[macro_export]
+macro_rules! field_path {
+    ($front:ident) => {{
+        $crate::FieldPath::from_name(stringify!($front))
+    }};
+    ($front:ident $(. $rest:ident)+) => {{
+        $crate::FieldPath::from_iter([
+            $crate::Field::from(stringify!($front)),
+            $($crate::Field::from(stringify!($rest))),+
+        ])
+    }};
+}
+
 impl FieldPath {
     /// The selector for the root (i.e., the top-level struct itself)
     pub fn root() -> Self {
@@ -350,7 +365,7 @@ mod tests {
     #[test]
     fn nested_field_not_found() {
         let dtype = DType::struct_([("a", DType::Bool(NonNullable))], NonNullable);
-        let path = FieldPath::from_name("b");
+        let path = field_path!(b);
         assert!(path.resolve(dtype.clone()).is_none());
         assert!(!path.exists_in(dtype.clone()));
 
@@ -365,7 +380,7 @@ mod tests {
             [("a", DType::Primitive(PType::I32, NonNullable))],
             NonNullable,
         );
-        let path = FieldPath::from_name("a").push("b");
+        let path = field_path!(a.b);
         assert!(path.resolve(dtype.clone()).is_none());
         assert!(!path.exists_in(dtype.clone()));
 

vortex-layout/src/layouts/path.rs

@@ -85,7 +85,7 @@ impl PathStrategy {
     ///
     /// ```no_run
     /// # use std::sync::Arc;
-    /// # use vortex_dtype::{Field, FieldPath};
+    /// # use vortex_dtype::{field_path, Field, FieldPath};
     /// # use vortex_layout::layouts::compact::CompactCompressor;
     /// # use vortex_layout::layouts::compressed::CompressingStrategy;
     /// # use vortex_layout::layouts::flat::writer::FlatLayoutStrategy;
@@ -105,7 +105,7 @@ impl PathStrategy {
     ///         Arc::new(compress_btrblocks),
     ///     )
     ///     .with_leaf_strategy(
-    ///         vec![Field::from("request"), Field::from("body"), Field::from("bytes")],
+    ///         vec![field_path!(request.body.bytes)],
     ///         Arc::new(compress_compact),
     ///     );
     /// ```