block error learning ruby on rails - ruby-on-rails

Question

i am teaching myself Ruby on rails i have got up to the tutorial on running the local web server. i have done everything up to this step and when i run rails server i get this error can someone explain what is going on in this error.
C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.3.4/lib/bundler/d
sl.rb:159:in `group': no block given (yield) (LocalJumpError)
from C:/Users/rto/Desktop/rails_projects/first_app/Gemfile:23:in `eval_g
emfile'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.3.4/
lib/bundler/dsl.rb:30:in `instance_eval'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.3.4/
lib/bundler/dsl.rb:30:in `eval_gemfile'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.3.4/
lib/bundler/dsl.rb:9:in `evaluate'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.3.4/
lib/bundler/definition.rb:19:in `build'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.3.4/
lib/bundler.rb:148:in `definition'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.3.4/
lib/bundler.rb:116:in `setup'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/bundler-1.3.4/
lib/bundler/setup.rb:7:in `<top (required)>'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/site_ruby/1.9.1/rubygems/core_
ext/kernel_require.rb:116:in `require'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/site_ruby/1.9.1/rubygems/core_
ext/kernel_require.rb:116:in `rescue in require'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/site_ruby/1.9.1/rubygems/core_
ext/kernel_require.rb:122:in `require'
from C:/Users/rto/Desktop/rails_projects/first_app/config/boot.rb:6:in `
<top (required)>'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/site_ruby/1.9.1/rubygems/core_
ext/kernel_require.rb:51:in `require'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/site_ruby/1.9.1/rubygems/core_
ext/kernel_require.rb:51:in `require'
from script/rails:5:in `<main>'
source 'https://rubygems.org'
gem 'rails', '3.2.13'
# Bundle edge Rails instead:
# gem 'rails', :git => 'git://github.com/rails/rails.git'
gem 'sqlite3',
# Gems used only for assets and not required
# in production environments by default.
group =>assets do
gem 'sass-rails', '~> 3.2.3'
gem 'coffee-rails', '~> 3.2.1'
# See https://github.com/sstephenson/execjs
#readme for more supported runtimes
# gem 'therubyracer', :platforms => :ruby
gem 'uglifier', '>= 1.0.3'
end
gem 'jquery-rails'
# To use ActiveModel has_secure_password
# gem 'bcrypt-ruby', '~> 3.0.0'
# To use Jbuilder templates for JSON
# gem 'jbuilder'
# Use unicorn as the app server
# gem 'unicorn'
# Deploy with Capistrano
# gem 'capistrano'
# To use debugger
# gem 'debugger'

Answer 1

group =>assets do
you are missing a colon in gemfile. Should read:
group :assets do

Answer 2

This is bundler complaining about missing blocks. I'd guess that your Gemfile is messed up. That is, you have there something like this
group :development
Whereas you are supposed to provide a block
group :development do
gem 'pry'
# other gems
end
Update:
You have several errors in your Gemfile
gem 'sqlite3',
This shouldn't have a comma
group =>assets do
This should be group :assets do

Answer 3

This error will occur when working with blocks.
When you used the 'yield' statement inside the method and didn't pass block as parameter then it will raise the 'no block given (yield) (LocalJumpError)' error.
def my_method
yield
end
puts my_method
In the above method call we are not passing parameter as a block so it will throw '(LocalJumpError) error'.
Here is the correct way to pass block as a parameter
def my_method
yield
end
puts my_method{puts 'something'}