defaults: &defaults
  adapter:  postgres
  host:     localhost
  <<: *defaults

development:
  database: myapp_development
  adapter:  postgres
  host:     localhost
  <<: *defaults

test:
  database: myapp_test
  <<: *defaults

int:
  - 
  - 0b1010_0111_0100_1010_1110    #二进制表示

key: 
    child-key

key2: 
    child-key: 
        key3: child-key

%YAML 1.2
---
!!seq [
   !!str "literal\n",
   !!str "·folded\n",
   !!str "keep\n\n",
   !!str "·strip",
]

%YAML 1.2
---
!!map {
   ? !!str "strip"
   : !!str "# text",
   ? !!str "clip"
   : !!str "# text\n",
   ? !!str "keep"
   : !!str "# text\n",
}