🧬 FnMeta

Returns metadata about a function at runtime.

Currently this includes the [TypeId]s of function parameters.

This includes a [FnMetadata] struct and [FnMetadataExt] trait. FnMetadataExt adds the .metadata() function on functions and closures to return a FnMetadata, whose implementation returns function metadata at runtime.

Usage

Add the following to Cargo.toml

```toml fn_meta = "0.7.2"

or

fnmeta = { version = "0.7.2", features = ["fnmeta_ext"] } ```

Code:

```rust use core::any::TypeId;

use fn_meta::{FnMetaDyn, FnMetadataExt};

fn f1(_: &S0, _: &mut S1, _: &S2) -> () {}

let fn_metadata = f1.metadata();

asserteq!( [TypeId::of::(), TypeId::of::()], fnmetadata.borrows().asslice() ); asserteq!([TypeId::of::()], fnmetadata.borrowmuts().as_slice());

struct S0; struct S1; struct S2; ```

Features

"fn_meta_ext":

Enables the FnMeta and FnMetaExt traits. FnMetaExt adds the .meta() function on functions and closures to return a Box<dyn FnMeta>, which is the dynamic dispatch analog to FnMetadata.

"high_arg_count":

Raises the number of arguments that [FnMetaExt] and [FnMetadataExt] are implemented for from 6 to 8.

This is feature gated because compilation time increasing significantly with higher numbers of arguments -- as much as from 1.5 seconds for 6 arguments to 8 seconds for 8 arguments.

License

Licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or https://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.