EO (stands for Elegant Objects) is an object-oriented programming language. It's still a prototype. It's the future of OOP. Please contribute!

If you want to contribute, please join our Gitter chat first.

These things we don't tolerate:

• static/class methods or attributes
• classes (only types and objects)
• implementation inheritance
• mutability
• NULL
• global variables/procedures
• reflection
• constants
• type casting
• scalar types
• garbage collection (huh?)
• annotations
• unchecked exceptions
• operators (for, while, if, etc)

These things we want to build in:

• static analysis
• continuous integration
• build automation
• aspects (AOP)
• logging
• unit testing
• versioning
• concurrency
• object metadata
• persistence
• transactions
• licensing
• artifact repositories

These things we are not sure about (please, help us):

• we don't need generics (not sure)
• we don't need private and protected methods
• we don't need public and protected attributes

We want EO to be compilable to Java. We want to stay as close to Java and JVM as possible, mostly in order to re-use the eco-system and libraries already available.

Quick Start

Here is a classic "hello, world" example:

import org.eolang.printed;
import org.eolang.string;
cli(
  printed(
    string("Hello, world!")
  )
)

This code will compile into a .java class that will compile into a .class byte code that will run and print "Hello, world!".

What exactly happens here? [a detailed explanation wanted]

The Language

That's all we have in the language:

• objects
• types
• methods
• attributes
• method arguments

Pay attention, we don't have:

• classes
• statements
• variables

This is how we define a type (similar to Java interface):

type Book {
  String asText();
}

This is how we create a new object:

create abc("The Alphabet") as Book {
  String isbn;
  String title;
  Book(ISBN i, String t):
    isbn(i),
    title(t);
  String asText() {
    copy sprintf(
      "ISBN is %s, title is '%s'",
      this.isbn,
      this.title
    )
  }
}

This is how we create another object, copying an existing one:

copy abc("Object Thinking")