It's Not Ruby, But… Miami Ruby Brigade March 19, 2018 

It's Not Ruby, But… • Polyglot Culture • Skills & Tools
 • Python • Elixir • Rust • Crystal 

Polyglot Culture vs. Contempt Culture 

Polyglot Culture Programming languages are cool and it's good there are like a million of 'em 

Polyglot Culture • Some are fun and are good to learn and crib concepts and ideas from • Some are really useful for a specific task • Some are pretty good at lots of things 

Polyglot Culture • No one programming language is good at everything • When a language is the best at one thing it's frequently really bad outside that 

Polyglot Culture So just learn lots 

Contempt Culture • it's real bad • makes people feel bad about their valuable time spent learning "contemptible" languages 

Contempt Culture • disproportionately targets languages used by people in more-marginalized groups 

Polyglot Culture vs. Contempt Culture • i've done php, java, and javascript professionally • and i enjoyed and learned from them all 

Polyglot Culture vs. Contempt Culture • it's okay to not like or avoid languages • but your reasons aren't everyone's reasons and your choices aren't everyone's choices 

Value and honor peoples' decisions to use what they do 

It's Not Ruby, But… • Polyglot Culture • Skills & Tools
 • Python • Elixir • Rust • Crystal 

Skills Programming is hard 

Skills • Getting a handle on a single programming language is a difficult proposition • Learning a second language is also hard • Being able to switch languages on the same project is even harder 

Skills • so gj everyone that can switch from ruby to js without forgetting: • parens around arguments • return statements • how prototypes work 

Skills • the more languages you learn, the easier it gets • especially if those languages are related somehow 

Tools • lots of stuff in ruby is available for other languages • package managers • syntax highlighting for your editor 

Tools • sometimes it's not great, depending on how fresh the language is • sometimes it's not great because the language just grew differently 

It's Not Ruby, But… • Polyglot Culture • Skills & Tools
 • Python • Elixir • Rust • Crystal 

Python • it's an interpreted object-oriented language from the '90s • Inspired Ruby! 

Python • scientific computing • program analysis • "computer hacking" 

Python • angr • binary ninja • pwntools 

import angr 
 import simuvex 
 import binaryninja 
 
 bv = binaryninja.BinaryViewType['ELF'].open('magic') 
 bv.update_analysis_and_wait() 
 
 sum_string = "sum is %ld\n" 
 strings = bv.get_strings() 
 sum_ref = [r for r in strings if 
 sum_string == bv.read(r.start, r.length)][0] 
 code_ref = bv.get_code_refs(sum_ref.start)[0] 
 main_start = bv.get_previous_function_start_before(code_ref.address) 
 main_func = bv.get_function_at(main_start) 
 main_return = [o for o in main_func.low_level_il.basic_blocks[0] if 
 binaryninja.enums.LowLevelILOperation.LLIL_RET == o.operation][0] 
 
 
 proj = angr.Project('magic', 
 load_options={'auto_load_libs': False}) 
 add_options={simuvex.o.BYPASS_UNSUPPORTED_SYSCALL} 
 path_group = proj.factory.path_group(threads=1) 
 path_group.explore(find=main_return.address) 
 
 print path_group.found[0].state.posix.dumps(0) 
 print path_group.found[0].state.posix.dumps(1) 

Why Python? • Libraries that aren't available in Ruby • Or aren't as good in Ruby • Documentation to do a thing that doesn't exist for Ruby 

Big Changes in Python • mandatory good indent style • without parens you get the function as a value instead of calling it • you need to return to return a value 

Big Changes in Python • global functions that call awkwardly-named methods instead of just methods • len(collection) or collection.__len__() • instead of collection.length() 

Big Changes in Python • Python package management developed parallel but independent from Ruby's • octopus eyes work a lot like human eyes but they evolved 'em completely differently 

Big Changes in Python • python 2 vs. python 3 • use python 3 when you can 

Small Changes in Python • nil is None, true is True, false is False • it's already installed with a whole pile of libraries • a lot of Linux distros use it 

It's Not Ruby, But… • Polyglot Culture • Skills & Tools
 • Python • Elixir • Rust • Crystal 

Elixir • erlang-like language with ruby syntax • made by Rails users 

Elixir • i already knew Ruby and Erlang so i picked up Elixir in a weekend 

It's Not Ruby, But… • Polyglot Culture • Skills & Tools
 • Python • Elixir • Rust • Crystal 

Rust • Mozilla made Rust because C++ doesn't do everything they need to • new by PL standards, first showed up in 2010 

Rust • a lot of the tooling was built by Ruby users 

Rust • you will hear people complain about the compiler being really picky • working as intended 

In most browsers, it would be hard to get this right. Parallelism is a known hard problem, and the CSS engine is very complex. It’s also sitting between the two other most complex parts of the rendering engine — the DOM and layout. So it would be easy to introduce a bug, and parallelism can result in bugs that are very hard to track down, called data races. […] With Rust, you can statically verify that you don’t have data races. This means you avoid tricky-to-debug bugs by just not letting them into your code in the first place. The compiler won’t let you do it. https:/ /hacks.mozilla.org/2017/08/inside-a-super-fast-css-engine-quantum-css-aka-stylo/ 

Rust Projects I've Done • sinatra-like webapps that call shell scripts • programs that get hacked but only the right way 

use std::net::UdpSocket; 
 
 fn main() { 
 let socket = UdpSocket::bind("0.0.0.0:1337"). 
 expect("failed to bind udp socket"); 
 
 socket. 
 set_read_timeout(None). 
 expect("couldn't set forever timeout"); 
 
 loop { 
 let mut buf: [u8; 32] = [0; 32]; 
 
 let (amt, src) = socket. 
 recv_from(&mut buf). 
 expect("failed to recv"); 
 
 assert!(amt == 32, "recvd {}, wanted 32", amt); 
 
 let expectation = [56, 55, 53, 53, 49, 99]; 
 
 if buf == expectation { 
 let reply ="nice!".as_bytes(); 
 
 socket. 
 send_to(reply, &src). 
 expect("failed to reply, rats"); 
 } 
 } 
 } 
 
 

Rust stuff worth looking at • Helix: use rust (instead of c) to write ruby modules 

Twitter to Mastodon • Nintendo Switch posts screenshots and videos to twitter and facebook • I want those on my Mastodon account 

Twitter to Mastodon • watch my tweets for #NintendoSwitch on the twitter streaming API • pick the best media version to post to mastodon • download the media • upload it to mastodon • post the toot 

Twitter to Mastodon • honestly it'd be a ruby program • want to fit it in spare memory on an ec2 instance • and not think too hard about it 

switch-tweet-copier • got to the media picker before i got tied up in types and compiler errors • JSON's type system vs. Rust's type system 

It's Not Ruby, But… • Polyglot Culture • Skills & Tools
 • Python • Elixir • Rust • Crystal 

Crystal • what if ruby but compiled to native bytecode 

private def process_media(tweet) 
 blank = [] of ::Mastodon::Entities::Attachment 
 extended_entities = tweet.extended_entities 
 return blank if extended_entities.nil? 
 media = extended_entities.media 
 return blank if media.nil? 
 
 media.map do |medium| 
 pp medium.type 
 
 case medium.type 
 when "video" 
 process_video(medium) 
 when "photo" 
 process_photo(medium) 
 else 
 nil 
 end 
 end.compact 
 end 
 

Crystal • I finished the project :3 • Only had to update a bunch of libraries "shards" by hands 

Changes in Crystal • "ruby" is "crystal" • "gems" are "shards" • "bundler" is built in 

Changes in Crystal • type annotations • Not a huge community 

It's Not Ruby, But… • Polyglot Culture • Skills & Tools
 • Python • Elixir • Rust • Crystal 

Conclusions • learn more languages • don't hate • lots of good languages for different tasks