FermiDirak

struct MyStruct { /* ... */ }
impl MyStruct {
    pub fn instance_method(&self) { /* ... */ };
}

// usage
let my_struct = MyStruct { /* ... */ }
my_struct.instance_method();

FermiDirak

// user_model.rs
struct UserModel { /* ... */ }
impl UserModel {
    pub fn fullname() -> String;
    // ...
}

// happy_birthday_service.rs
pub fn send_message(session_context: &SessionContext, /* ... */) {
    let message = session_context.user.happy_birthday_message();

FermiDirak

// UserModel.ts
type UserModel = { /* ... */ }
namespace UserService {
    function fullName(): string { /* ... */ };
    // ...
}

// HappyBirthdayService.ts
function sendMessage(sessionContext: &SessionContext) {
    let message = happyBirthdayMessage(sessionContext.user);

FermiDirak

// consuming `apply_move` immutably
let chess_state = Chess::starting_board();
let player_move = Move { start: ('G', 1), end: ('F', 3) };
let next_state = {
    let mut next_state = chess_state.clone();
    next_state.apply_move(player_move);
    next_state
};

FermiDirak

// mutations are explicitly opt in
let mut chess_game = Chess::starting_board();
let player_move = Move { start: ('G', 1), end: ('F', 3) };
chess_game.apply_move(player_move);

FermiDirak

use serde::{Serialize, Deserialize};

#[derive(Serialize, Deserialize)]
pub enum PlayerSide { /* ... */ }
#[derive(Serialize, Deserialize)]
pub struct Move { /* ... */ }
#[derive(Serialize, Deserialize)]
pub struct Board { /* ... */ }
#[derive(Serialize, Deserialize)]
pub struct Chess { board: Board, turn: PlayerSide }

FermiDirak

enum PlayerSide { /* ... */ }
type Move = { /* ... */ }
type Board = { /* ... */ }
type Chess = { board: Board; turn: PlayerSide }

namespace ChessService {
    // functions for interacting with the game chess
    function applyMove(chess: Chess, move: Move): Chess { /* ... */ }
    function starting_state(): Chess { /* ... */ }
    function listValidMoves(board: Chess, playerTurn: PlayerSide): Move[] { /* ... */ }

FermiDirak

import jscodeshift from "jscodeshift";
import fs from "fs";
import path from "path";

const projectDirectory = "my/project/root/directory";

///////////////////////////////////////////////////////////////////////////////
// util functions
///////////////////////////////////////////////////////////////////////////////

FermiDirak

import {getSourceFilesIterator, lsFiles} from "react-codestats";

const sourceFileIterator = getSourceFilesIterator("~/flexport/javascripts", {
  extensions: ["js", "jsx"],
  withParser: "flow",
});

let formulaOneImports = 0;
let formComponentImports = 0;

FermiDirak

import iconNames from "latitude/iconNamesEnum";
import {getSourceFilesIterator} from "react-codestats";

const sourceFileIterator = getSourceFilesIterator("~/flexport/javascripts", {
  extensions: ["js", "jsx"],
  withParser: "flow",
});

const iconUsageCounts = iconNames.reduce((acc, iconName) => {
  acc.set(iconName, 0);