js-yaml 5 tails

[puzrin]

Summary of existng design issues. Those should be solved to make a new major version.

General

• Consider change parser approach
  • seems we have unresolveable problems like [reader] Reading of properties on implicit block mapping keys. #62 , ? Unexpected indent #292
  • we could fallback to reference model with events layer
  • we could store intermadiate tokens in typed array and get much more effecient scanner (see CSSTree approach)
• Better error messages for extra EOL, Extra EOL breaking line numbers #218 (ask spec devs)
• ? Example 8.18. Implicit Block Mapping Entries = fails to parse #257
• ? YAML 1.2 spec: Example 8.2. Block Indentation Indicator #253
• ? not able to parse anchor variable reference #301, Can't tokenize alias as key without seperator #319
• ? Example 7.5 "Double Quoted Line Breaks" of the 1.2 spec is not parsed properly #307

Javascrpt-related

• It would be nice to have .strinigify() / .parse() methods, like JSON.
  • exact JSON schema?
  • what about Date / Regexp support?
• Map / Set support
  • How to distinguish map syntax? Users prefer Object in most cases - much more convenient.
  • What about old browsers? We could suggest use Map / Set polyfills, but some basic (SJON-like) functionality should work out of box.
  • also see Trying to use an object as a key results in the string '[object Object]' as a key #169

Unsure

• Loader must throw an error on zero-indentation block scalar #280