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use mlua::{chunk, Lua, MetaMethod, Result, UserData};
#[derive(Default)]
struct Rectangle {
length: u32,
width: u32,
}
impl UserData for Rectangle {
fn add_fields<'lua, F: mlua::UserDataFields<'lua, Self>>(fields: &mut F) {
fields.add_field_method_get("length", |_, this| Ok(this.length));
fields.add_field_method_set("length", |_, this, val| {
this.length = val;
Ok(())
});
fields.add_field_method_get("width", |_, this| Ok(this.width));
fields.add_field_method_set("width", |_, this, val| {
this.width = val;
Ok(())
});
}
fn add_methods<'lua, M: mlua::UserDataMethods<'lua, Self>>(methods: &mut M) {
methods.add_method("area", |_, this, ()| Ok(this.length * this.width));
methods.add_method("diagonal", |_, this, ()| {
Ok((this.length.pow(2) as f64 + this.width.pow(2) as f64).sqrt())
});
// Constructor
methods.add_meta_function(MetaMethod::Call, |_, ()| Ok(Rectangle::default()));
}
}
fn main() -> Result<()> {
let lua = Lua::new();
let rectangle = Rectangle::default();
lua.load(chunk! {
local rect = $rectangle()
rect.width = 10
rect.length = 5
assert(rect:area() == 50)
assert(rect:diagonal() - 11.1803 < 0.0001)
})
.exec()
}
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