polars_structpath_derive

This crate provides procedural derive macros for the polars_structpath ecosystem. It automatically generates implementations of the StructPath and EnumPath traits, enabling dynamic path-based access to nested Rust structures.

Purpose

polars_structpath_derive is a procedural macro crate that generates code for:

• StructPath derive macro: Automatically implements the StructPath trait for structs, enabling path-based field access
• EnumPath derive macro: Automatically implements the EnumPath trait for enums, enabling path-based enum value access with case conversion support

This crate is used by:

• polars_structpath: The main user-facing library that re-exports these derive macros
• End users: Who apply #[derive(StructPath)] or #[derive(EnumPath)] to their structs and enums

Usage

StructPath

Apply the #[derive(StructPath)] attribute to structs with named fields:

use polars_structpath::StructPath;

#[derive(StructPath)]
struct User {
    name: String,
    age: i64,
    #[type_hint("struct")]
    parent: Option<Parent>,
}

#[derive(StructPath)]
struct Parent {
    name: String,
}

The #[type_hint] attribute can be used to provide type information for complex types like nested structs, enums, or collections.

EnumPath

Apply the #[derive(EnumPath)] attribute to enums:

use polars_structpath::EnumPath;

#[derive(EnumPath)]
#[enum_path(camel_case_to_upper_snake_case)]
enum Status {
    Active,
    Inactive,
}

The #[enum_path] attribute supports case conversion functions for mapping enum variant names to string representations.

See Also

• Main README - Overview of the entire polars_structpath ecosystem
• polars_structpath - User-facing API documentation
• polars_structpath_types - Core types and traits
• polars_protobuf - Protocol Buffers integration