Crate rlua_builders

The rlua-builders crate provides helpers for Rust/Lua interop using rlua. That means creating Rust struct/enums from Lua with almost the same syntax as in Rust!

This crate itself only provides a trait definition, but rlua-builders-derive provides derive macros to automatically implement the defined trait for any struct or enum. It just needs to have UserData implemented for it. After that, simply call StructOrEnum::builder(ctx) to create a builder for that struct or enum.

What do these builders look like?

• For unit structs: A builder is simply the unit value itself, which can be converted to Lua since the struct implements UserData.
• For tuple structs: A builder is a lua function that receives the tuple arguments in order and returns the userdata for the struct.
• For normal structs: A builder is a lua function that receives a single table with the named arguments to the struct.
• For enums: A builder is a table where each field is a builder for each of the enum's variants, and each of them works the same way as the struct builders defined above.

Examples:

This shows how to derive and use LuaBuilder on a simple struct. See rlua for more documentation on how to interop with Lua.

use rlua::UserData;
use rlua_builders::LuaBuilder;
use rlua_builders_derive::{LuaBuilder, UserData};

#[derive(LuaBuilder, UserData, Clone, PartialEq, Debug)]
struct Person {
    name: String,
    age: u8,
}

let p = rlua::Lua::new().context(|ctx| {
    ctx.globals().set("Person", Person::builder(ctx)?)?;
    ctx.load(r#"Person { name = "Yan", age = 24 }"#).eval::<Person>()
}).unwrap();

assert_eq!(p, Person {name: "Yan".to_owned(), age: 24})

Enums work in a similar way, except their constructor is a table where each function is equivalent to a struct builder.

#[derive(LuaBuilder, UserData, Clone)]
enum Valuables {
    Coins(u32),
    Book {name: String},
    Knowledge,
}

If later binded to lua

ctx.globals().set("Valuables", Valuables::builder(ctx)?)?;

Can be used in a very similar way to Rust

local a = Valuables.Coins(12)
local b = Valuables.Knowledge
local c = Valuables.Book { name = "A Dance with Dragons" }

Traits

LuaBuilder

A struct or enum with this Trait provides a Lua builder.