Question

I’m trying to get Less up and running on my system and I’m running into an error.

Steps taken so far

gem install less
rails plugin install git://github.com/cloudhead/more.git
# restart everything
# moved styles.css to app/stylesheets/styles.less
rake more:generate

Hopefully, running the last line will create styles.css in public/stylesheets from the .less source. But, I get the error:

Generating css from less files in app/stylesheets.
rake aborted!
uninitialized constant Less::Engine
From /Users/sanj/Documents/sanj/applyco/app/stylesheets/my_formtastic_changes.less
/Users/sanj/.rvm/gems/ruby-1.9.2-p0/gems/aws-s3-0.6.2/lib/aws/s3/extensions.rb:206:in `const_missing_from_s3_library'
/Users/sanj/Documents/sanj/applyco/vendor/plugins/more/lib/less/more.rb:122:in `block in compile'
/Users/sanj/Documents/sanj/applyco/vendor/plugins/more/lib/less/more.rb:122:in `open'
/Users/sanj/Documents/sanj/applyco/vendor/plugins/more/lib/less/more.rb:122:in `compile'
/Users/sanj/Documents/sanj/applyco/vendor/plugins/more/lib/less/more.rb:62:in `generate'
/Users/sanj/Documents/sanj/applyco/vendor/plugins/more/lib/less/more.rb:77:in `block in generate_all'
/Users/sanj/Documents/sanj/applyco/vendor/plugins/more/lib/less/more.rb:76:in `each'
/Users/sanj/Documents/sanj/applyco/vendor/plugins/more/lib/less/more.rb:76:in `generate_all'
/Users/sanj/Documents/sanj/applyco/vendor/plugins/more/lib/tasks/more_tasks.rake:5:in `block (2 levels) in <top (required)>'
/Users/sanj/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:636:in `call'
/Users/sanj/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:636:in `block in execute'
/Users/sanj/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:631:in `each'
/Users/sanj/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:631:in `execute'
/Users/sanj/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:597:in `block in invoke_with_call_chain'
/Users/sanj/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
/Users/sanj/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain'
/Users/sanj/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:583:in `invoke'
/Users/sanj/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:2051:in `invoke_task'
/Users/sanj/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:2029:in `block (2 levels) in top_level'
/Users/sanj/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:2029:in `each'
/Users/sanj/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:2029:in `block in top_level'
/Users/sanj/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling'
/Users/sanj/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:2023:in `top_level'
/Users/sanj/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:2001:in `block in run'
/Users/sanj/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling'
/Users/sanj/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/lib/rake.rb:1998:in `run'
/Users/sanj/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.8.7/bin/rake:31:in `<top (required)>'
/Users/sanj/.rvm/gems/ruby-1.9.2-p0/bin/rake:19:in `load'
/Users/sanj/.rvm/gems/ruby-1.9.2-p0/bin/rake:19:in `<main>'

What’s going on?

Setup:

Ruby 1.9.2, Rails 3.0
Mac OS X
Less 2.0.5

Answer 1

Well it looks this line in more is causing the error when it calls engine = File.open(file){|f| Less::Engine.new(f) } and looking at the source code for Less project in the old code they do define the Less::Engine however they have moved the gem over to a new version which has included some changes to the source and does not define Less::Engine.

I would recommend you follow the instructions on the official less website to get up and running. It seems like the more plugin is no longer supported.