Design of the public API

[Nadrieril]

The current focus of the Dhall project is "displacing YAML". I would like for dhall-rust to go in this direction as well.
So the current objective is: what would be the simplest API we can imagine that would enable people to consume Dhall files as easily as YAML, but also profit from the power of Dhall ?

Currently, the API provides (more-or-less) a dhall::from_str(s) function that can be used as a drop-in replacement for serde_yaml::from_str(s). That's a good start, but I think this is too minimal.

What kind of things should we include in the API ? What kind of code would you like to write using this crate ?

[Nadrieril]

Some ideas:

• enable/disable import resolution
• something like dhall::from_str_with_type(s, type) that checks that the parsed expression has the given type
• I have written a macro that derives a Dhall type for a given Rust type (see e.g. this test). For example, struct Foo { field1: u64, field2: Option<bool> } becomes the Dhall type { field1: Natural, field2: Optional Bool }. How do we use this ?

[Nadrieril]

Some ideas of the kind of code we could want to write:

// A type
let point_type_str = "{ x: Natural, y: Natural }";
// Parse the type
let point_type = dhall::from_str(point_type_str)?;

// Some Dhall data
let point_str = "{ x = 1, y = 1 + 1 }";
// Deserialize it to a Rust type, checking against the provided type.
let deserialized_map: HashMap<String, u64> =
      dhall::from_str_with_type(point_str, &point_type)?;

use serde::Deserialize;

#[derive(Debug, Deserialize, MagicDhallType)]
struct Point {
    x: u64,
    y: u64,
}

// Some dhall data
let point_str = "{ x = 1, y = 1 + 1 }";

// Convert the dhall string to a Point, checking against the inferred type.
let point: Point = dhall::from_str_with_magic_type(point_str)?;

[Nadrieril]

With #100 we got something I'm happy with, so I'm closing this.