Generate yaml node anchors and references programmatically

Question

I need to generate this yaml programmatically in Rails:

foo: &foo
  x: 1
  y: 2

bar:
  <<: *foo
  z: 3

which when it's parsed should give this hash:

output = {
    :foo => {
        :x => 1,
        :y => 2
    },
    :bar => {
        :x => 1,
        :y => 2,
        :z => 3
    }
}

Obviously output.to_yaml gives the expanded syntax. Is there any way to output the yml syntax with anchor and nodes programmatically.

[this might be relevant](http://stackoverflow.com/questions/11665897/read-and-write-yaml-files-without-destroying-anchors-and-aliases) — jtzero, Dec 27 '12 at 20:31
@OMG the yaml snipped posted at the beginning of the question. — Fabio, Jun 21 '13 at 12:57
why you are not looking [`YAML`](http://yard.ruby-doc.org/stdlib-2.0/YAML.html)? — Arup Rakshit, Jul 07 '13 at 07:55

score 0 · Answer 1 · answered Oct 08 '13 at 04:03

I had a similar feature where i read from an initializer many YAML files and appended to a global variable. it is something like this:

APP = Hash.new
Dir.glob("#{Rails.root}/config/data/*.yml").each do |file|
  fdata = File.open(file).read
  APP.merge!(YAML::load(ERB.new(fdata).result(binding)).symbolize_keys!)
end

I should know more about your problem to write a more specific solution.

The main point is the YAML::load method, which reads de yaml formated text and outputs a hash. the ERB is because Yaml files could contain erb tags which should be interpreted. It could or could not be needed. symbolize_keys! is for accessing with [:symbols] and not ["strings"] to keys.

Generate yaml node anchors and references programmatically

1 Answers1