https://github.com/llogiq/momo

A Rust proc_macro_attribute to outline conversions from generic functions
https://github.com/llogiq/momo

hacktoberfest monomorphization

Last synced: 6 days ago
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A Rust proc_macro_attribute to outline conversions from generic functions

• Host: GitHub
• URL: https://github.com/llogiq/momo
• Owner: llogiq
• License: apache-2.0
• Created: 2019-05-17T22:00:43.000Z (over 5 years ago)
• Default Branch: master
• Last Pushed: 2024-05-30T13:45:03.000Z (7 months ago)
• Last Synced: 2024-12-07T04:16:54.287Z (20 days ago)
• Topics: hacktoberfest, monomorphization
• Language: Rust
• Homepage:
• Size: 534 KB
• Stars: 264
• Watchers: 11
• Forks: 8
• Open Issues: 11
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# momo

**Keep your compile time during MOnoMOrphization**

[![badge](https://docs.rs/momo/badge.svg)](https://docs.rs/momo)

This is a `proc_macro` crate to help keeping the code footprint of

generic methods in check. Often, generics are used in libraries to

improve ergonomics.  However,  this has a cost in compile time and

binary size.  Optimally,  one creates a  small shell function that

does the generic conversions and then calls an inner function, but

that makes the code less readable.

Add a `#[momo]`  annotation from this crate to split your function

into an outer conversion and a private inner function.  In return,

you get some compile time for a tiny bit of runtime (if at all) –

without impairing readability.

Conversions currently supported are `Into` (`.into()`), `AsRef`

(`.as_ref()`), and `AsMut` (`.as_mut()`).  See `enum Conversions`

in code.

## Notes on watt

This new updated version uses D. Tolnay's [watt] runtime to speed

up the compile time, which was negatively affected with proc macro

baggage.

The main crate uses a pre-built wasm containing the tagged version.

Rebuilding the wasm can be done with the commands:

```bash

cd wasm

cargo +nightly build \

    --release \

    --target wasm32-unknown-unknown \

    -Z build-std=std,panic_abort \

    -Z build-std-features=panic_immediate_abort

# If wasm-opt is unavailable, copying the file is fine.

wasm-opt target/wasm32-unknown-unknown/release/momo_watt.wasm -Oz \

--strip-debug --simplify-globals --vacuum -o ../src/momo.wasm

```

You might need to add the  `wasm32-unknown-unknown` target to your

Rust toolchain.

[watt]: https://github.com/dtolnay/watt

(If you are tagging a new version, remember to commit the new `wasm` file.

Also change the versions in both `Cargo.toml` files.)

## Debugging the macro

The [cargo-expand] tool may be used to expand the output of macro expansion,

including from this proc-macro.  To examine the results of the example file,

use `cargo expand --example check`.

[cargo-expand]: https://github.com/dtolnay/cargo-expand