Seeing Metaprogramming and Lambda Function Patterns in Ruby

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Seeing Metaprogramming And Lambda Function Patterns in Ruby Lukas Nimmo [email protected]

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Geology Minerals

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Ruby is beautiful so our DSLs should be beautiful

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Implementation Interfaces: The Ruby Way Complexity Public Interface

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Compare

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Roadmap Goals/Problems Public Interface Implementation

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Case #1: Trust Issues

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Goal Provide configuration options while handling quality assurance

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Typical Ways of Setting up an Object/Library Object Initialization: One by One:

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Goal Provide configuration options while handling quality assurance

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Railsconfig/Config Public Interface

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Railsconfig’s Implementation: The Block

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Geocoder Public Interface

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Geocoder’s Implementation: The Hash

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Block vs Hash

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Case #2: Situational Language

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Goal Offer Situational Language

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Typical Example of Creating Flexibility One path: Several Paths:

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Goal Offer Situational Language

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Hike RSpec Public Interface

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Hike’s Implementation One path: Several Paths: Condensed Situational Language

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Common conditions for Situational Language Singular vs. Plural: path and paths

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Common conditions for Situational Language Synonyms

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Common conditions for Situational Language Grammatically correct options

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Con: Cognitive Load

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Case #3: Leveraging APIs

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Goal Leveraging generally accepted meaning of existing APIs

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How Polyglot Might Alter Kernel

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Public Interface Polyglot

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Polyglot’s Implementation Still Accessible How it looks now:

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Problem? Original New

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Public Interface

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Case #4: Declarative DSLs

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Declarative DSL’s for setting up classes in your domain Goal

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Rails/ActiveRecord

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Declarative DSL’s for setting up classes in your domain Goal

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Rails/ActiveRecord Public Interface

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ActiveRecord’s Implementation

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Case #5: Domain Switching

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Define behavior in a familiar domain and execute elsewhere Goal

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Sinatra Public Interface

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Define behavior in a familiar domain and execute elsewhere Goal

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Sinatra’s Implementation

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Case #6: Opening Doorways

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Allow many entries around the same structure Goal

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Clockwork Faraday Accessing Library Structures

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Allow many entries around the same structure Goal

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Clockwork Module Instance Class Public Interface

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Clockwork’s Implementation

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Faraday Public Interface

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Faraday’s Implementation

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Case #7: Dynamic Building

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Dynamically build objects with the broadest interface possible Goal

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Typical Object Building

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Dynamically build objects with the broadest interface possible Goal

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JBuilder Public Interface

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JBuilder’s Implementation

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Paint :my_scheme is now a module Public Interface

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Paint’s Implementation

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What is the pattern really?

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Implementation Interfaces: The Ruby Way Complexity Public Interface

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Situation Solution Trust Issues Singleton Situational Language alias_method Leveraging Existing APIs Around Alias and Module#prepend Declarative DSLs Class Macros Domain Switching class_eval + Lambdas/Procs/Blocks Opening Doorways Hooks and Method Delegation Dynamic Building method_mising and const_missing

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Questions? Lukas Nimmo [email protected]