```ruby
require 'projecta'

class ProjectB < Application
  
  git 'https://github.com/rjud/ProjectB.git'
  
  cmake do
    option :BUILD_WITH_A, :BOOLEAN, desc: 'Build with A'
    option :ProjectA_DIR, :PATH, cond: :BUILD_WITH_A, default: ProjectA.new.prefix.join('share', 'projecta', 'cmake').to_s
  end
  
  ctest
  
  depend_on ProjectA, :BUILD_WITH_A
  
end
```

Read the prefix of another project must be delayed
user
```ruby
require 'projecta'

class ProjectB < Application
  
  git 'https://github.com/rjud/ProjectB.git'
  
  cmake do
    option :BUILD_WITH_A, :BOOLEAN, desc: 'Build with A'
    option :ProjectA_DIR, :PATH, cond: :BUILD_WITH_A, default: lambda { ProjectA.new.prefix.join('share', 'projecta', 'cmake').to_s }
  end
  
  ctest
  
  depend_on ProjectA, :BUILD_WITH_A
  
end
```
assistant