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The design goals for YAML:-YAML is easily readable by humans.-YAML data is portable between programming languages.-YAML matches the native data structures of agile languages.-YAML has a consistent model to support generic tools.-YAML supports one-pass processing.-YAML is expressive and extensible.-YAML is easy to implement and use.

A collection of Awesome YAML (Ain't Markup Language) goodies for structured (meta) data in text.

YAML HQ

• yaml.org - official YAML website by Clark C. Evans
  • YAML Spec v1.2 - 3rd edition, Oct 2009
  • YAML Quick Reference Card - one-page cheat sheet

• strictyaml - a type-safe YAML parser that parses and validates a restricted subset of the YAML specification
  • YAML Features Removed
    • NO Implicit Typing
    • NO Direct representations of objects
    • NO Duplicate Keys Disallowed
    • NO Explicit tags
    • NO Node anchors and refs
    • NO Flow style

"Safer" YAML - YAML Redux

• nestedtext.org,(github) - a human friendly data format similar to YAML but without the complexity and risk of YAML

Example:

# Contact information for our officerspresident:    name: Katheryn McDaniel    address:        > 138 Almond Street        > Topeka, Kansas 20697    phone:        cell: 1-210-555-5297        home: 1-210-555-8470            # Katheryn prefers that we always call her on her cell phone.    email: KateMcD@aol.com    additional roles:        - board member

• YAML Quick Reference (Cheat Sheet) for Jekyll Data Files, Front Matter and Collections, Planet Jekyll
• Learn YAML in Y Minutes, Learn X in Y minutes series,
• Deep dive into TOML, JSON and YAML, Go Hugo HQ, Dec 2016
• YAML @ Wikipedia

Strings with Colons (:)

When to use quotes for your strings?

If your string includes a colon (:) followed by a space you MUST quote your string. Otherwise, the colon is interpreted as a key/value separator (e.g.key: value). Example:

title:"Text Processing with Ruby: Extract Value from the Data That Surrounds You"title:"Sinatra: Up and Running - Ruby for the Web, Simply"title:"Using JRuby: Bringing Ruby to Java"

Note: You can quote your strings using double quotes ("") e.g. "Using JRuby: Bringing Ruby to Java"or single quotes('') e.g. 'Using JRuby: Bringing Ruby to Java'.

No Tabs (\t) for Indentation - Use Spaces, Period

Note: Always use spaces for indentation, period.Make sure no tabs (\t) have somehow ended up in your datafile leading tounexpected results.

Predefined Boolean 'n' No Value Constants - True/False, Yes/No, On/Off, ~/Null

Note: The booleantrue andfalse constants e.g.:

true, True, TRUEy, Y, yes, YES, YESon, ON, ONfalse, False, FALSEn, N, no, No, NOoff, Off, OFF

will become boolean values e.g.true orfalse. If you want end-up with a string e.g.:

recommend:Yes# note: will become => true (boolean)

make sure you use a quoted version e.g.:

recommend:"Yes"# note: will become => "Yes" (string)

Note: The same holds for the no value null constants e.g.:

~null, Null, NULL

will become =>null (no value). Note: A key without a value will end-up with anull value (and not an empty string, for example). To get an empty string use"" e.g.:

key1:# note: value will become => null (no value); same as key1: null  or key1: ~key2:""# note: value will become => "" (string)

JSON is (a subset of) YAML, that is YAML is JSON but JSON is NOT YAML ;-)

Example: Use the inline style for lists (that is, JSON arrays)and hashes (that is, JSON objects) for an alternative "JSON-style" syntax:

[  {"title":"football.db - Open Football Data","url":"https://github.com/openfootball"   },  {"title":"beer.db - Open Beer, Brewery 'n' Brewpub Data","url":"https://github.com/openbeer"   }]

is the same as:

-title:football.db - Open Football Dataurl:https://github.com/openfootball-title:beer.db - Open Beer, Brewery 'n' Brewpub Dataurl:https://github.com/openbeer

• YAML Linter @ yamllint.com - online YAML validator / checker
• YAML Validator @ Code Beautify - online YAML validator / checker
• YAML Comparator @ yamline - online YAML comparator
• Yamlinc - compose multiple files using $include tag / compiler
• dasel ("data-selector") - Query and update data structures using selectors from the command line. Comparable tojq /yq but supports JSON, YAML, TOML and XML with zero runtime dependencies.

No:Body:Wants:To:Write:          -YAML

• noyaml.com,(github) - a rant about the state of devops tooling / the infrastructure sector

Mandatory "No Body Wants To Write YAML" reading list:

• Today we’re going to look at some general problems with the YAML format
• We replaced 1,000 lines of YAML with 10 structs and people started contributing again
• What if you used the same language and tools you use to define your app to define your infrastructure?
• A YAML file is almost always still 'valid' even if it is trunca
• The bug was that the YAML parser ignored the negative signs ... so negative GPS coordinates became positive ones
• Every YAML parser is a custom YAML parser
• There are 63 different ways to write multi-line strings in YAML

• Feed.TXT - web feed format with meta data in YAML
• YAML @ Stackoverflow - frequently asked questions (and answers) about YAML
• Manifest - a complete backend in 1 YAML file

License

The awesome list is dedicated to the public domain. Use it as you please with no restrictions whatsoever.

Questions? Comments?

Post them to thewwwmake forum. Thanks!