yamly

⚠️ work in progress

A type-safe and loose parser for a reasonable yaml dialect (i.e. not the full yaml specs, but what you usually find around). Parses yaml code directly to Nim types as in jsony. Indeed the implementation is a port of jsony to yaml.

Somewhat inspired by (Python library) strictyaml for the idea that you should better give up on full Yaml specs and and target a reasonable dialect (but I plan to support flow style).. For a complete yaml 1.2 parser, use NimYAML. For another take of a restricted yaml parser, check out nyml. Ah, there is also yanyl.

Features of Yaml that are not in scope of implementation:

• directives (stuff with %)
• anchors (&) and refs (*) and <<
• tagging with ! or !!
• complex mapping keys (which use ?)
• yaml set type (e.g. a list that uses ? instead of -, or other formats). Note that a list can be parsed as set if the type is specified to be a nim bit set or hash set.
• cannot use tab for whitespace anywhere (in yaml you cannot use tab for indentation but you can use it for generic whitespace)

todo

• refactor to use YamlParseContext and YamlDumpContext?
• refactor split in parse and dump separate submodules
• symbols
  • numbers
    • dump
    • parse
    • octal and hex
  • bool
  • enum
• containers
  • object
    • dump
      • dump key that needs to be quoted (e.g. starts with ", contains invalid characters, ...)
    • parse
    • flow-style
  • sequence
    • dump
    • parse
    • flow-style
  • tuple
  • array
    • dump
  • sets
  • tables
• string (non quoted, quoted and multiline)
• null
• "json"
• distinct
• document separator? which api?

dev notes

• (!=yaml) disallowing tab in spaces
• (!=jsony) parseHook requires an indentation field
• (!=jsony) not implementing fast dumping and parsing of numbers
• (!=jsony) using unittest (I like the check output in case of failing test)
• (!=jsony) refactor api using YamlParseContext/YamlDumpcontext instead of exposing s, idx, ind in signatures
• (!=jsony) refactor: parse and dump are two separate modules

interesting features not (yet) present in jsony:

• strict mode
• easy way to skip fields when dumping
• automatic camel to snake when dumping?