Planned ideas for APIs

[huachaohuang]

Let me write down some planned ideas for APIs that are not going to deliver in 0.3 here.

Strongly-typed collections

The benefits of strongly-typed collections:

• Data is safer and easier to understand since it is guaranteed to be the specific type
• Potentially allow the internal server/engine to optimize for some specific access pattern if it knows the data type

However, the currently supported collections are actually dynamically-typed despite the type notation in clients. This means that the server doesn't guarantee that all objects in the collection have the same type.

To support strongly-typed collections, we need to allow users to specify the type when they create collections.

Conditional transactions

The easiest to understand conditions are something like compare-and-swap (CAS). The Rust API maybe some like this:

object.when(condition).add(1);

Selection / Projection

The current APIs mostly focus on writes. We should support more advanced collection-level read operations. We can model the interface from Rust Iterator. For example, we may allow users to do this:

collection.filter(condition).map(projection);

Container member operations

We may allow users to do more operations on container members. For example, if we have a collection with the type List<Int64>, we can support something like:

collection.object("a").at(0).add(1);

Support object options

For example, TTL

[w41ter]

I have two questions,

1. How to express condition and projection in rust? Such as complex AND, OR operations.
2. What happen if the at(0) operations goes out of bounds?

[huachaohuang]

1. How to express condition and projection in rust? Such as complex AND, OR operations.

It can be expressed like this:

object.when(|x| and(x.exists(), or(x.gt(10, x.lt(20))).do(something);

This means that "if the object exists and (its value > 10 or < 20), do something".

2. What happen if the at(0) operations goes out of bounds?

We should return a logical error to the user.

[huachaohuang]

Filter expressions can be expressed in the same way as conditional transactions.