walnut

Walnut is a new interface for persistent state.

Want to save something to disk? Create a 'Walnut Object' like so:

haru = :dog.(name: "Haru")

...and it's been saved!

Want to get all the :dog's?

irb> :dog.all
=> [:dog.(name: "Haru")]

We can get a single dog by name:

irb> haru = :dog.find_one(name: "Haru")
=> :dog.(name: "Haru")

This data is persisted in the ./store directory. Any time you mutate a field of a Walnut Object, the change gets persisted immediately to disk:

irb> haru.name = 'Haru the Dog'
irb> `cat store/dog-*`
=> "{\"name\":\"Haru the Dog\"}

Lastly, we can use find_many to filter by a particular attribute:

irb> :dog.(name: "Momo")
irb> :dog.all
=> [:dog.(name: "Haru the Dog"), :dog.(name: "Momo")]
irb> :dog.find_many(name: "Momo")
=> [:dog.(name: "Momo")]

installation

git clone https://github.com/charlesetc/walnut
make

And now irb -r walnut should work.

future work

Support for atomic transactions.
It would be nice to have a better story/pattern for changing the data layout, i.e. some standardization of migrations.
When an object is removed, its references should be too. How would this play with non-null type guarantees? Maybe you can only remove if there are no references?

todos

describe sub-references in the readme
recursive references aren't supported well at the moment
add homogeneous data constraint