main.rs

// Apparently, this needs to be *before* I actually import the fucking mod
// wat.
use player::*;
mod player;

fn main() {
	let mut stats = vec![
		Stat::new("HP".to_string(), player::default_advancer_fn),
		Stat::new("SP".to_string(), player::default_advancer_fn),
		Stat::new("ATK".to_string(), player::default_advancer_fn),
		Stat::new("DEF".to_string(), player::default_advancer_fn)
	];
	stats[0].advance(1200);
	stats[1].advance(800);
	stats[2].advance(4000);
	stats[3].advance(250);

	let p = Player::new("holo".to_string(), stats);
	for stat in p.stats {
		println!("{}: {}", stat.skill, stat.level);
	}
}

player.rs

pub type AdvancerFn = fn(exp: u32) -> u32;
pub struct Stat {
	pub skill: String,
	pub exp: u32,
	pub level: u32,
	advancer: AdvancerFn,
}

impl Stat {
	pub fn new(name: String, advancer: AdvancerFn) -> Stat {
		let exp = 0;
		return Stat {
			skill: name,
			exp: exp,
			level: advancer(exp),
			advancer: advancer
		}
	}
	pub fn advance(&mut self, exp: u32) -> u32 {
		let lv = self.level;
		self.exp += exp;
		self.level = (self.advancer)(self.exp);
		return self.level - lv;
	}
}

// insert exp, receive current level
pub fn default_advancer_fn(exp: u32) -> u32 {
	return exp / 100;
}

pub struct Player {
	pub name: String,
	pub stats: Vec<Stat>
}

impl Player {
	pub fn new(name: String, stats: Vec<Stat>) -> Player {
		return Player {
			name:  name,
			stats: stats
		}
	}
}