Implementing Ruby

Personal experiments.

Created by @ajlopez

https://github.com/ajlopez/Talks/tree/master/ImplementingRuby https://github.com/ajlopez/RubySharp

Using reveal.js

Ruby

A dynamic language

Smalltalk Influence
Also Python, Perl, Lisp, ...
Dynamic Type System
Memory Management

Only one Ruby?

Ruby
JRuby
IronRuby
Rubinius
MacRuby
HotRuby
mruby
...

Interpreters

The easy approach

How Do Interpreters Work?

Read some source code
Build an AST (Abstract Syntax Tree) by parsing the source code
Evaluate the program by walking over the AST and performing instructions

Compilers for free

## AST ```ruby x = 2; y = x * 3 ``` ![AST](images/ast01.png)

MRI

Matz's Ruby Interpreter
Also called CRuby
de facto reference

Compilers

How Do Compilers Work?

Read some source code
Build an AST by parsing the source code
Generate target code by walking the AST and emitting instructions

Compilers for free

## Virtual Machine, Bytecodes ```js x = 2; y = x * 3 ``` ![AST](images/bc01.png)

YARV

YARV (Yet another Ruby VM)
The official Ruby implementation for Ruby 1.9

Rubinius

http://rubini.us/

Designed for concurrency
Native threads to run Ruby code on all the CPU cores
LLVM-based just-in-time (JIT) native machine code compiler

An Implementation

Ruby in C#

Challenges

Modules and Classes
Class Hierarchy
Namespaces
Singleton Classes
Garbage Collector
Load .Dlls

Lexer and Parser

Everything is a Value

To be evaluated in Context

Test-Driven Development

Put your money where your mouth is!

## Bootstrap ```csharp public Machine() { this.requirepaths.Add("."); var basicobjectclass = new DynamicClass("BasicObject", null); var objectclass = new ModuleObject("Object", basicobjectclass); var moduleclass = new ModuleClass(objectclass); var classclass = new ClassClass(moduleclass, objectclass); this.rootcontext.SetLocalValue("BasicObject", basicobjectclass); this.rootcontext.SetLocalValue("Object", objectclass); this.rootcontext.SetLocalValue("Module", moduleclass); this.rootcontext.SetLocalValue("Class", classclass); basicobjectclass.SetClass(classclass); objectclass.SetClass(classclass); moduleclass.SetClass(classclass); classclass.SetClass(classclass); // ... ``` To be SIMPLIFIED!!

Things to Explore

https://github.com/ajlopez/RuScript