ferray-core-macros

Procedural-macro support crate for ferray-core.

Part of the ferray workspace.

Overview

This is a proc-macro crate (proc-macro = true). It exports the compile-time machinery that ferray-core relies on for record types, slicing syntax, and type promotion:

• #[derive(FerrayRecord)] — derives unsafe impl ferray_core::record::FerrayRecord for a #[repr(C)] struct with named fields. The generated field_descriptors() builds a static slice of FieldDescriptor (name, dtype, offset, size per field, via Element::dtype() / offset_of! / size_of), and record_size() returns size_of::<Self>(). Emits a compile error if the struct is not #[repr(C)], is not a struct, or lacks named fields.
• s![...] — NumPy-style slice macro. Expands a comma-separated list of axis specifiers into a Vec<ferray_core::dtype::SliceInfoElem>. Supports integer indices (s![3]), full/partial ranges (s![..], s![2..], s![..5], s![1..5]), and a ;step suffix (s![1..5;2]).
• promoted_type!(T1, T2) — compile-time type promotion. Resolves two numeric types to the smallest common type following NumPy's promotion rules (e.g. promoted_type!(i32, f32) → f64, promoted_type!(u8, i8) → i16). Covers bool, the signed/unsigned integers, f16/bf16, f32/f64, and Complex<f32>/Complex<f64>. Emits a compile error when no lossless common type exists (e.g. u128 + a signed integer).

Usage

This is internal infrastructure, normally pulled in transitively by ferray-core; you should not depend on it directly — use ferray or ferray-core instead, which re-export the macros at their public paths. A minimal #[derive(FerrayRecord)] example:

use ferray_core::record::FerrayRecord;

#[repr(C)]
#[derive(FerrayRecord)]
struct Point {
    x: f64,
    y: f64,
    id: i32,
}

let descriptors = Point::field_descriptors();
assert_eq!(descriptors.len(), 3);
assert_eq!(Point::record_size(), std::mem::size_of::<Point>());

Feature flags

None. The crate has no [features] table.

MSRV & edition

• Edition: 2024
• MSRV: 1.88
• License: MIT OR Apache-2.0