Dockerfile

# FROM crystallang/crystal:0.36.1-alpine
FROM crystallang/crystal@sha256:ee97e1ef8b609cd80a8d504fdf8c5c09f7ac2fc520d360a7b10c8d50aa21f4b2

COPY . .

RUN crystal build --static --error-trace yaml.cr

yaml.cr

require "yaml"

data = YAML.parse <<-END
         ---
         foo:
           bar:
             baz:
               - qux
               - fox
         END

puts data["foo"]["bar"]["baz"][1].as_s