How to use the debugger with Ruby 2.0?
The debugger gem can be used but it still has issues. Install byebug which was written for Ruby 2.0 debugging. For breakpoints, use the byebug command in your code instead of debugger.
ruby-2.0
Comparability Issue rails 4 beta, ruby 2.0.0, mongoid
Use mongoid master from github, that has support for rails 4.0. gem ‘mongoid’, git: ‘https://github.com/mongoid/mongoid.git’
Garbage collector tuning in Ruby 2.0
There’s a fair bit of confusion about these GC tuning parameters. REE (which is a fork of Ruby 1.8.7) introduced its own parameters first, and later Ruby (starting in 1.9.2) introduced its own (similar) parameters. Ruby 1.9.3 made them customizable via environment variables, and Ruby 2.1.0 added a lot more. This blog post goes into … Read more
What is the difference between ‘include’ and ‘prepend’ in Ruby?
What features of Module are defined as append and prepend? As specified in the text you quoted: the constants, methods, and module variables How they differ functionally? Both add methods of the mixed-in module to the passed module (class). The difference is in the lookup order of these methods, in case that the target class … Read more
Ruby on Rails – “Add ‘gem sqlite3” to your Gemfile”
In my case, this error “Specified ‘sqlite3’ for database adapter, but the gem is not loaded. Add gem ‘sqlite3’ to your Gemfile.” message showed up, when I ran rails server right after I generated a fresh rails app. It was with Rails version 4.1.16 (Ruby version 2.3.1) gem ‘sqlite3’, ‘~> 1.3.0’ This line in Gemfile … Read more
How to improve memory sharing between unicorn processes with Ruby 2.0 on Linux
According to this answer, which you may have already seen, there is a line that reads: Note that a “share-able” page is counted as a private mapping until it is actually shared. i.e. if there is only one process currently using libfoo, that library’s text section will appear in the process’s private mappings. It will … Read more
Named parameters in Ruby 2
I think that the answer to your updated question can be explained with explicit examples. In the example below you have optional parameters in an explicit order: def show_name_and_address(name=”Someone”, address=”Somewhere”) puts “#{name}, #{address}” end show_name_and_address #=> ‘Someone, Somewhere’ show_name_and_address(‘Andy’) #=> ‘Andy, Somewhere’ The named parameter approach is different. It still allows you to provide defaults … Read more
Uninstalling all gems Ruby 2.0.0
I used this one line script. for i in `gem list –no-versions`; do gem uninstall -aIx $i; done It ignores default gem errors and just proceeds. Simple and self-evident.
Can I have required named parameters in Ruby 2.x?
There is no specific way in Ruby 2.0.0, but you can do it Ruby 2.1.0, with syntax like def foo(a:, b:) … In Ruby 2.0.x, you can enforce it by placing any expression raising an exception, e.g.: def say(greeting: raise “greeting is required”) # … end If you plan on doing this a lot (and … Read more
Unexpected Return (LocalJumpError)
You can’t return inside a block in Ruby*. The last statement becomes the return value, so you can just remove the return statements in your case: p (1..8).collect{|denom| (1…denom).collect{|num| r = Rational(num, denom) if r > Rational(1, 3) and r < Rational(1, 2) 1 else 0 end } }.flatten *: You can inside lambda blocks: … Read more