toml config, take 2

[karmacoma-eth]

New design principles

• names, types and default values defined in a plain Config dataclass
  • easy to parse, pickle and pass around, with well defined property names
  • Config dataclasses are immutable
• config file loaded separately through basic toml, applies overrides to the default Config
• the arg parser can be generated from the Config dataclass and has no defaults, it applies overrides to the config object again
• the arg parser can still be reused for contract level and test level dev docs, and should require no copy because it has no defaults (so it only adds overrides for explicit parameters)

Advantages:

• no external dependencies
• the Config dataclass is the source of truth for parameter names, values, types and defaults
  • easy to go to the definition of a setting
• the override order is very clear and explicit
• Config objects are aware of their parents, so when you request a value from a child, it checks first in itself and falls back to its parent
  • 👍 no copies
  • 👍 explainable (you can print a test config and see the source for each parameter — default, file, CLI, contract or test devdocs)
• should be easy to generate a sample config file with up to date defaults too

[karmacoma-eth]

different take on #125

[daejunpark]

😍

[karmacoma-eth]

I'll add a full halmos.toml example in a follow up