Crystal: A Better Ruby?

Serdar Doğruyol

@sdogruyol

• Open Source Wizard
• Rubyist
• Crystal contributor / evangelist
• Kemal author
• Polyglot

Serdar Doğruyol

• Dynamically typed
• Metaprogramming
• GIL
• No async
• Legacy / Weird Stuff

Ruby

Dynamically Typed

def full_name(first_name, last_name)
  first_name + last_name
end

NoMethodError: undefined method `+' for nil:NilClass

Metaprogramming

• #send
• #eval
• #define_method
• ....

BUT

RUNTIME IS SLOOO..........W

GIL

a.k.a

I WONT INTERPRET YOUR CODE IN PARALLEL

No Async

Just use concurrent-ruby

Guilds?

ko1's proposal for Ruby 3.0 

Legacy / Weird Stuff

Double Quotes

VS

Single Quotes

ENGRISH

include? anyone

require

load

autoload

Bazillions of aliases

#size

#length

Ruby is awesome!

• Statically typed
• Macros
• LLVM
• CSP
• NO Legacy / Weird Stuff

Crystal

Statically Typed

def full_name(first_name, last_name)
  first_name + last_name
end

crystal build full_name.cr

./full_name

Error in line 5: instantiating 'full_name(Nil, String)' in line 2: undefined method '+' for Nil

Macros

• NO #send
• NO #eval
• NO RUN-TIME

COMPILE-TIME

LLVM

--release

free optimizations!

CSP

a.k.a

Communicating Sequential Processes

require "socket"

channel = Channel(String).new

spawn do
  server = TCPServer.new("0.0.0.0", 8080)
  socket = server.accept
  while line = socket.gets
    channel.send(line)
  end
end

spawn do
  while line = gets
    channel.send("Echo: #{line}")
  end
end

loop do
  puts channel.receive
end

No Legacy / Weird Stuff

ENGLISH

includes?

contains?

require

No Aliases

class Human
  
  def initialize(@first_name, @last_name, @skills)
  end

end

Human.new "Serdar", "Dogruyol", ["ruby", "crystal"]

crystal tool format

crystal play

Union Types

Int32 | String

Crystal is awesome!

Thanks

@sdogruyol

https://slides.com/sdogruyol/crystal-a-better-ruby