RubyMotion: Under the Hood

RubyMotion:Under the Hood

Inspired by Click and Clack

Monday, October 14, 2013

A brief introduction


Name:

About Me

Joshua BallancoMonday, October 14, 2013

Employer: Burnside Digital

About Me


Ankara, Turkey

About Me

Location:Monday, October 14, 2013

A slightly longer introduction


Before...


Employer: Patch

About Me


New York City

About Me


Before that...


Employer: Apple

About Me


Cupertino

About Me


Before that...


School: University of Miami

About Me


Miami

About Me


A bit of history


In graduate school


At Apple... Retail


At Apple

Laurent Sansonetti


After Apple...


Episode VI - The Return of The RubyMotion


What is RubyMotion?

• Use Ruby to build apps for iOS and OS X

• Native apps

• Interface directly with Obj-C libraries

• CLI-based build system


What is RubyMotion?

• RubyMotion: http://www.rubymotion.com/

• MotionCasts: http://motioncasts.tv/

• RubyMotion Wrappers:

! http://rubymotion-wrappers.com/

• ...and lot’s more


http://www.rubymotion.com/

http://www.rubymotion.com/

http://motioncasts.tv/

http://motioncasts.tv/

http://rubymotion-wrappers.com/

http://rubymotion-wrappers.com/

What is MacRuby?

• Intended to be the implementation of Ruby 2.0 for OS X

• Target RubySpec compliance

• JIT or AOT Compiled

• Uses libauto for Garbage Collection


What is MacRuby?Ruby Syntax

Parser

Compiler

VM (sans GVL) LLVM (with JIT)

Objective-C Runtime


Ruby Syntax

Parser

Compiler

VM (sans GVL) LLVM (with JIT)

Objective-C Runtime

Running a “something.rb” file


Ruby Syntax

Parser

Compiler

VM (sans GVL) LLVM

Objective-C Runtime

AOT compiling “something.rb”

something.o


Parser

Compiler

something.oVM (sans GVL)

Objective-C Runtime

Running an AOT compiled “something.rb”


Parser

Compiler

LLVM

something.oVM (sans GVL)

Objective-C Runtime

Running an AOT compiled “something.rb”


What is RubyMotion?

• Descendent of MacRuby

• “Ruby, the Good Parts”

• Static Compiled

• Retain/release reference counting


Ruby Syntax

Parser

Compiler

VM (sans GVL) LLVM

Objective-C Runtime

Static compiling “something.rb”

something.o


VM (sans GVL)

Objective-C Runtime

Running a static compiled “something.rb”

something.o


Why must we statically compile?

• On OS X

• Compile writes code to a memory page

• Runtime runs the code from that memory page


Why must we statically compile?

• On iOS

• Memory pages must be writable or executable, NOT BOTH!

• OS prohibits runtime compilation

• Apple prohibits interpreting arbitrary scripts

• ...but you wouldn’t want an interpreter anyway


Garbage Collection


What happened to the Garbage Collector?

It required extra threads, so we had to kill it...


So RubyMotion Uses ARC?

Yes...

Uh...no

...sorta?


ARC vs “ARC”

• Objective-C’s ARC modifies your code before compilation

• RubyMotion VM knows when retain and/or release should be called...your code is not touched


ARC vs “ARC”

Isn’t the distinction rather academic?

Probably...


“ARC” Caveats• Collection happens when the autorelease

pool drains

• Need to be careful with tight loops that generate many objects

• Use “autorelease do...end”

• Detects almost all cycles

• Use WeakRefs if cycles become problematic


Debugging RubyMotion

• Remember, RubyMotion objects are Objective-C objects...

• All the usual tricks are valid!


Let’s Play!


The Victimapp/app_delegate.rb


REPL Magic


That’s cool...but can you do it in a debugger???


Debugger Wizardry


That’s CRAZY!

I know...but it’s fun!


Debugging RubyMotion

• Helper methods “pro” and “pri”

• http://www.rubymotion.com/developer-center/articles/debugging/

• Watch for more/better tooling to come...


Questions?

@manhattanmetric

Joshua Ballanco

https://github.com/jballanc


RubyMotion: Under the Hood

Technology

Transcript of RubyMotion: Under the Hood