Advanced Ruby for Rails developers 

What are we talking about? Ruby claims to make things easier for developers, but sometimes that flexibility feels like complexity. For example, Ruby supports 4 different ways to reference (and later execute) a piece of code: - methods - blocks - procs - lambdas 

We’re talking about: methods and blocks 

We’re talking about: dynamic methods 

We’re talking about: procs and lambdas what if ... you could treat code as if it were data or an object? that’s what procs and lambdas do for you. they let you wrap code and pass it around in variables and collections. and the two are essentially the same thing except for a little syntax and 2 differences in behavior. 

We’re talking about: procs and lambdas both of them are closures (they keep a reference to the current context) and respond to the call() method 

We’re talking about: lambdas Lambdas: - enforce arity - return to the scope in which they were called 

We’re talking about: procs Procs: - don’t enforce arity - return to the scope in which they were defined 

Time Check… let’s code? 

We’re talking about: open source for study Sample Project: GitLab - github.com/gitlabhq/gitlabhq - Self hosted Git management software Fast and easy Git repositories, hosted either on your own or at Gitlab.com. Create projects and repositories, manage access and perform collaborative code reviews. - 200,000 lines of code and 600 classes among 2800 files 

We’re talking about: Rails link sample project: GitLab 

We’re talking about: Rails guides.rubyonrails.org/active_record_querying.html 

We’re talking about: Rails body.call() 

We’re talking about: Rails sample project: GitLab link 

We’re talking about: Rails api.rubyonrails.org /classes/AbstractController/Callbacks/ClassMethods.html 

We’re talking about: Rails 

summary - Ruby let’s you “name” a piece of code to run later. - methods and blocks can’t be passed around like objects - procs and lambdas can. what else? - embrace the confusion - have faith in your own work - keep exploring, playfully 

- Questions? - check out opensourcerails.com - thanks! Sherif Abushadi [email protected]