blackmwk commented on code in PR #3044:
URL: https://github.com/apache/iceberg-rust/pull/3044#discussion_r3877716724
##########
crates/property-macro/README.md:
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@@ -271,3 +275,68 @@ converted into their field type with `Into`.
`from_properties` and both custom parser hooks use `iceberg::Result`. Generated
`FromStr` failures use `ErrorKind::DataInvalid`. The macro preserves errors
from
custom parsers and adds the primary property key as error context.
+
+## `properties_view!` function-like macro
+
+`properties_view!` independently defines a lightweight borrowed view over a
+flat property map. Its struct-shaped fields are declarations used to generate
+getters rather than stored fields. Constructing the view does not parse
+anything; each generated getter parses and returns only its declared property.
+Missing properties use their annotated defaults, while invalid configured
+values return an error from the corresponding getter.
+
+```rust
+use std::collections::HashMap;
+
+use iceberg_property_macro::properties_view;
+
+properties_view! {
+ #[derive(Debug)]
+ pub struct WriteProperties {
+ // `getter` makes a generated getter public. Without it, the getter is
+ // private, regardless of the declaration's visibility modifier.
+
+ /// Number of times to retry a commit.
+ #[property(key = "commit.retry.num-retries", default = 4, getter)]
+ commit_num_retries: usize,
+
+ /// Optional configured base directory for metadata files.
+ #[property(key = "write.metadata.path", default = None)]
+ raw_write_metadata_path: Option<String>,
+ }
+}
+
+impl WriteProperties<'_> {
+ /// Returns the configured metadata path or the table's metadata directory.
+ pub fn write_metadata_path(&self, table_path: &str) ->
iceberg::Result<String> {
+ Ok(self.raw_write_metadata_path()?.unwrap_or_else(|| {
+ format!("{}/metadata", table_path.trim_end_matches('/'))
+ }))
+ }
+}
+
+fn read(properties: &HashMap<String, String>) -> iceberg::Result<()> {
+ let view = WriteProperties::new(properties);
+ let _retries = view.commit_num_retries()?;
+ let _metadata_path = view.write_metadata_path("s3://bucket/table")?;
+ Ok(())
+}
+```
+
+The generated type has one lifetime parameter and contains only a reference to
Review Comment:
Done. The example now documents the generated constructor signature and
lifetime, explains that its visibility matches the view declaration, and
clarifies that construction only stores the map reference without parsing.
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