YAML – The language

• YAML is a markup language that dates back to 2001 by Clark Evants.

  Originally it’s named as Yet Another Markup Language.

• It’s human-readable data serialization format.

  The purpose is to focus on data, than on doucmentation markup.

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Features

• Provides structures that can be easily mapped to common data types in most high-level languages including:

  • list
  • associative array
  • scalar

• Indented outline and lean apperance

  • suited for configuration files
  • documentation headers like Markdown file header
  • well-suited for hierarchical data representation

• Line and whitespace delimiters are friendly to grep/perl/python/ruby operations

• Very easy for human read/write

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Basic elements

• Lists

• Conventional block format use hyphen+space to begin a new item – just like markdown syntax, exmple:

   ---#Favoriate movies
   - Casablanca
   - Roman Holiday
   - Kill Bill
  

• Optional inline format use JSON similar syntax, like

   [milk, pie, eggs, juice]
  

• Associate array

• Keys are seperated from values by colon+space, like

      name: John Smith
      age: 33
  

• Inline blocks, like python dict

      {name: John Smith, age: 33}
  

• Block literal – strings don’t require quotation.

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Basic elements

• Lists of associative arrays – can be composed by any of the format

    - {name:John, age:22}
    - name: Jason
      age: 27
  

• Associative array of lists – can be composed by any of the format

    men: [John, Bill]
    women: 
        - Mary
        - Susan
  

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Reference

The wiki page can be found Here.