# `nsys` design doc
## Conventions
'Variant' -- newtype enum
'Kind' -- variant tag or newtype conversion trait
'Id', 'Key', 'Index'
- Id -- unique identifier, could be composite
- Key -- a newtype wrapper for a smaller primint index, otherwise another map
key type (e.g. a hashable instance)
- Index -- a usize or smaller primint type
num_X -- specifies the total number of something
X_count -- counts occurrences of something
Constructors:
- `fn default() -> Self` -- no params, can't fail
- `fn new (...) -> Option <Self>` -- safe constructor
- `fn noisy (...) -> Self` -- runtime assertion if constraints are violated
- `fn unchecked (...) -> Self` -- debug assertion if constraints are violated
