book

Ruby Under a Microscope

Name: Ruby Under a Microscope
Author: Pat Shaughnessy
ISBN: 9781593275273

by Pat Shaughnessy

November 2013

Intermediate to advanced

360 pages

9h 7m

English

No Starch Press

Read now

Unlock full access

Ruby Under a Microscope: An Illustrated Guide to Ruby Internals
Dedication
Advance Praise for Ruby under a Microscope
About the Author
Foreword
Acknowledgments
Introduction
Who This Book Is ForUsing Ruby to Test ItselfWhich Implementation of Ruby?Overview
1. Tokenization and Parsing
Tokens: The Words That Make Up the Ruby LanguageExperiment 1-1: Using Ripper to Tokenize Different Ruby ScriptsParsing: How Ruby Understands Your CodeUnderstanding the LALR Parse AlgorithmSome Actual Ruby Grammar RulesExperiment 1-2: Using Ripper to Parse Different Ruby ScriptsSummary
2. Compilation
No Compiler for Ruby 1.8Ruby 1.9 and 2.0 Introduce a CompilerHow Ruby Compiles a Simple ScriptCompiling a Call to a BlockExperiment 2-1: Displaying YARV InstructionsThe Local TableCompiling Optional ArgumentsCompiling Keyword ArgumentsExperiment 2-2: Displaying the Local TableSummary
3. How Ruby Executes Your Code
YARV’s Internal Stack and Your Ruby StackStepping Through How Ruby Executes a Simple ScriptExecuting a Call to a BlockExperiment 3-1: Benchmarking Ruby 2.0 and Ruby 1.9 vs. Ruby 1.8Local and Dynamic Access of Ruby VariablesLocal Variable AccessMethod Arguments Are Treated Like Local VariablesDynamic Variable AccessExperiment 3-2: Exploring Special VariablesSummary

4. Control Structures and Method Dispatch
How Ruby Executes an if StatementJumping from One Scope to AnotherCatch TablesOther Uses for Catch TablesExperiment 4-1: Testing How Ruby Implements for Loops InternallyThe send Instruction: Ruby’s Most Complex Control StructureMethod Lookup and Method DispatchEleven Types of Ruby MethodsCalling Normal Ruby MethodsPreparing Arguments for Normal Ruby MethodsCalling Built-In Ruby MethodsCalling attr_reader and attr_writerMethod Dispatch Optimizes attr_reader and attr_writerExperiment 4-2: Exploring How Ruby Implements Keyword ArgumentsSummary
5. Objects and Classes
Inside a Ruby ObjectInspecting klass and ivptrVisualizing Two Instances of One ClassGeneric ObjectsSimple Ruby Values Don’t Require a Structure at AllDo Generic Objects Have Instance Variables?Where Does Ruby Save Instance Variables for Generic Objects?Experiment 5-1: How Long Does It Take to Save a New Instance Variable?What’s Inside the RClass Structure?InheritanceClass Instance Variables vs. Class VariablesGetting and Setting Class VariablesConstantsThe Actual RClass StructureExperiment 5-2: Where Does Ruby Save Class Methods?Summary
6. Method Lookup and Constant Lookup
How Ruby Implements ModulesModules Are ClassesIncluding a Module into a ClassRuby’s Method Lookup AlgorithmA Method Lookup ExampleThe Method Lookup Algorithm in ActionMultiple Inheritance in RubyThe Global Method CacheThe Inline Method CacheClearing Ruby’s Method CachesIncluding Two Modules into One ClassIncluding One Module into AnotherA Module#prepend ExampleHow Ruby Implements Module#prependExperiment 6-1: Modifying a Module After Including ItClasses See Methods Added to a Module LaterClasses Don’t See Submodules Included LaterIncluded Classes Share the Method Table with the Original ModuleConstant LookupFinding a Constant in a SuperclassHow Does Ruby Find a Constant in the Parent Namespace?Lexical Scope in RubyCreating a Constant for a New Class or ModuleFinding a Constant in the Parent Namespace Using Lexical ScopeRuby’s Constant Lookup AlgorithmExperiment 6-2: Which Constant Will Ruby Find First?Ruby’s Actual Constant Lookup AlgorithmSummary
7. The Hash Table: The Workhorse of Ruby Internals
Hash Tables in RubySaving a Value in a Hash TableRetrieving a Value from a Hash TableExperiment 7-1: Retrieving a Value from Hashes of Varying SizesHow Hash Tables Expand to Accommodate More ValuesHash CollisionsRehashing EntriesExperiment 7-2: Inserting One New Element into Hashes of Varying SizesHow Ruby Implements Hash FunctionsExperiment 7-3: Using Objects as Keys in a HashHash Optimization in Ruby 2.0Summary
8. How Ruby Borrowed a Decades-Old Idea from Lisp
Blocks: Closures in RubyStepping Through How Ruby Calls a BlockBorrowing an Idea from 1975Experiment 8-1: Which Is Faster: A while Loop or Passing a Block to each?Lambdas and Procs: Treating a Function as a First-Class CitizenStack vs. Heap MemoryA Closer Look at How Ruby Saves a String ValueHow Ruby Creates a LambdaHow Ruby Calls a LambdaThe Proc ObjectExperiment 8-2: Changing Local Variables After Calling lambdaCalling lambda More Than Once in the Same ScopeSummary
9. Metaprogramming
Alternative Ways to Define MethodsRuby’s Normal Method Definition ProcessDefining Class Methods Using an Object PrefixDefining Class Methods Using a New Lexical ScopeDefining Methods Using Singleton ClassesDefining Methods Using Singleton Classes in a Lexical ScopeCreating RefinementsUsing RefinementsExperiment 9-1: Who Am I? How self Changes with Lexical Scopeself in the Top Scopeself in a Class Scopeself in a Metaclass Scopeself Inside a Class MethodMetaprogramming and Closures: eval, instance_eval, and bindingCode That Writes CodeCalling eval with bindingAn instance_eval ExampleAnother Important Part of Ruby Closuresinstance_eval Changes self to the Receiverinstance_eval Creates a Singleton Class for a New Lexical ScopeExperiment 9-2: Using a Closure to Define a MethodUsing define_methodMethods Acting as ClosuresSummary
10. JRuby: Ruby on the JVM
Running Programs with MRI and JRubyHow JRuby Parses and Compiles Your CodeHow JRuby Executes Your CodeImplementing Ruby Classes with Java ClassesExperiment 10-1: Monitoring JRuby’s Just-in-Time CompilerExperiment CodeUsing the -J-XX:+PrintCompilation OptionDoes JIT Speed Up Your JRuby Program?Strings in JRuby and MRIHow JRuby and MRI Save String DataCopy-on-WriteExperiment 10-2: Measuring Copy-on-Write PerformanceCreating a Unique, Nonshared StringExperiment CodeVisualizing Copy-on-WriteModifying a Shared String Is SlowerSummary
11. Rubinius: Ruby Implemented with Ruby
The Rubinius Kernel and Virtual MachineTokenization and ParsingUsing Ruby to Compile RubyRubinius Bytecode InstructionsRuby and C++ Working TogetherImplementing Ruby Objects with C++ ObjectsExperiment 11-1: Comparing Backtraces in MRI and RubiniusBacktraces in RubiniusArrays in Rubinius and MRIArrays Inside of MRIArrays Inside of RubiniusExperiment 11-2: Exploring the Rubinius Implementation of Array#shiftReading Array#shiftModifying Array#shiftSummary
12. Garbage Collection in MRI, JRuby, and Rubinius
Garbage Collectors Solve Three ProblemsGarbage Collection in MRI: Mark and SweepThe Free ListMarkingHow Does MRI Mark Live Objects?SweepingLazy SweepingDisadvantages of Mark and SweepExperiment 12-1: Seeing MRI Garbage Collection in ActionSeeing MRI Perform a Lazy SweepSeeing MRI Perform a Full CollectionInterpreting a GC Profile ReportGarbage Collection in JRuby and RubiniusCopying Garbage CollectionBump AllocationThe Semi-Space AlgorithmThe Eden HeapGenerational Garbage CollectionThe Weak Generational HypothesisUsing the Semi-Space Algorithm for Young ObjectsPromoting ObjectsGarbage Collection for Mature ObjectsConcurrent Garbage CollectionMarking While the Object Graph ChangesTricolor MarkingThree Garbage Collectors in the JVMExperiment 12-2: Using Verbose GC Mode in JRubyTriggering Major CollectionsFurther ReadingSummary
Index
Copyright

Content preview from Ruby Under a Microscope

Chapter 10. JRuby: Ruby on the JVM

JRuby is Ruby implemented on the Java platform.

In Chapter 1 through Chapter 9 we learned how the standard version of Ruby works internally. Because Ruby is written in C, its standard implementation is often known as CRuby. It’s also often referred to as Matz’s Ruby Interpreter (MRI), after Yukihiro Matsumoto, who created the language in the early 1990s.

In this chapter we’ll see an alternative implementation of Ruby called JRuby. JRuby is Ruby implemented in Java instead of C. The use of Java allows Ruby applications to run like any other Java program, using the Java Virtual Machine (JVM). It also allows your Ruby ...

Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.

Read now

Unlock full access

More than 5,000 organizations count on O’Reilly

O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.

Julian F.

Head of Cybersecurity

I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.

Addison B.

Field Engineer

I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.

Amir M.

Data Platform Tech Lead

I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.

Mark W.

Embedded Software Engineer

The Ruby Way: Solutions and Techniques in Ruby Programming, Third Edition

Publisher Resources

ISBN: 9781457185243Errata

Cloud Computing

Data Engineering

Data Science

AI & ML

Programming Languages

Software Architecture

IT/Ops

Security

Design

Business

Soft Skills

Ruby Under a Microscope

by Pat Shaughnessy

Chapter 10. JRuby: Ruby on the JVM

Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.