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|
use crate::options::{HasAnnot, ManualAnnot, NoAnnot, StaticAnnot, TypeAnnot};
use crate::{Result, SimpleType, ToDhall};
/// Controls how a Dhall value is written.
///
/// This builder exposes the ability to configure how a value is serialized, and to set type
/// annotations.
///
/// When using [`Serializer`], you'll create it with [`serialize()`], then chain calls to methods
/// to set each option, then call [`to_string()`]. This will give you a [`Result`] containing the
/// input serialized to Dhall.
///
/// Note that if you do not provide a type annotation, some values may not be convertible to Dhall,
/// like empty lists or enums.
///
/// [`to_string()`]: Serializer::to_string()
///
/// # Examples
///
/// Serializing without a type annotation:
///
/// ```rust
/// # fn main() -> serde_dhall::Result<()> {
/// use serde_dhall::serialize;
///
/// let string = serialize(&1i64).to_string()?;
/// assert_eq!(string, "+1".to_string());
/// # Ok(())
/// # }
/// ```
///
/// Serializing with an automatic type annotation:
///
/// ```rust
/// # fn main() -> serde_dhall::Result<()> {
/// use serde_dhall::serialize;
///
/// let data: Option<u64> = None;
/// let string = serialize(&data).static_type_annotation().to_string()?;
/// assert_eq!(string, "None Natural".to_string());
/// # Ok(())
/// # }
/// ```
#[derive(Debug, Clone)]
pub struct Serializer<'a, T, A> {
data: &'a T,
annot: A,
}
impl<'a, T> Serializer<'a, T, NoAnnot> {
/// Provides a type to the serialization process. The provided value will be checked against
/// that type, and the type will be used when Dhall needs it, like for empty lists or for
/// unions.
///
/// In many cases the Dhall type that corresponds to a Rust type can be inferred automatically.
/// See the [`StaticType`] trait and the [`static_type_annotation()`] method for that.
///
/// # Example
///
/// ```
/// # fn main() -> serde_dhall::Result<()> {
/// use serde_dhall::{serialize, from_str, SimpleType, SimpleValue};
///
/// let ty = from_str("< A | B: Bool >").parse()?;
/// let data = SimpleValue::Union("A".to_string(), None);
/// let string = serialize(&data)
/// .type_annotation(&ty)
/// .to_string()?;
/// assert_eq!(string, "< A | B: Bool >.A".to_string());
///
/// // Invalid data fails the type validation; serialization would have succeeded otherwise.
/// let ty = SimpleType::Integer;
/// assert!(
/// serialize(&Some(0u64))
/// .type_annotation(&ty)
/// .to_string()
/// .is_err()
/// );
/// # Ok(())
/// # }
/// ```
///
/// [`StaticType`]: crate::StaticType
/// [`static_type_annotation()`]: Serializer::static_type_annotation()
pub fn type_annotation<'ty>(
self,
ty: &'ty SimpleType,
) -> Serializer<'a, T, ManualAnnot<'ty>> {
Serializer {
annot: ManualAnnot(ty),
data: self.data,
}
}
/// Uses the type of `T` in the serialization process. This will be used when Dhall needs it,
/// like for empty lists or for unions.
///
/// `T` must implement the [`StaticType`] trait. If it doesn't, you can use [`type_annotation()`]
///
/// # Example
///
/// ```
/// # fn main() -> serde_dhall::Result<()> {
/// use serde::Serialize;
/// use serde_dhall::{serialize, StaticType};
///
/// #[derive(Serialize, StaticType)]
/// enum MyOption {
/// MyNone,
/// MySome(u64),
/// }
///
/// let data = MyOption::MySome(0);
/// let string = serialize(&data)
/// .static_type_annotation()
/// .to_string()?;
/// // The resulting Dhall string depends on the type annotation; it could not have been
/// // printed without it.
/// assert_eq!(string, "< MyNone | MySome: Natural >.MySome 0".to_string());
/// # Ok(())
/// # }
/// ```
///
/// [`StaticType`]: crate::StaticType
/// [`type_annotation()`]: Serializer::type_annotation()
pub fn static_type_annotation(self) -> Serializer<'a, T, StaticAnnot> {
Serializer {
annot: StaticAnnot,
data: self.data,
}
}
}
impl<'a, T, A> Serializer<'a, T, A>
where
A: TypeAnnot,
{
/// Prints the chosen value with the options provided.
///
/// If you enabled static annotations, `T` is required to implement [`StaticType`].
///
/// Note that if you do not provide a type annotation, some values may not be convertible to
/// Dhall, like empty lists or enums.
///
///
/// # Example
///
/// ```rust
/// # fn main() -> serde_dhall::Result<()> {
/// use serde_dhall::serialize;
///
/// let string = serialize(&1i64).static_type_annotation().to_string()?;
/// assert_eq!(string, "+1".to_string());
/// # Ok(())
/// # }
/// ```
///
/// [`StaticType`]: crate::StaticType
pub fn to_string(&self) -> Result<String>
where
T: ToDhall + HasAnnot<A>,
{
let val = self.data.to_dhall(T::get_annot(self.annot).as_ref())?;
Ok(val.to_string())
}
}
/// Serialize a value to a string of Dhall text.
///
/// This returns a [`Serializer`] object. Call the [`to_string()`] method to get the serialized
/// value, or use other [`Serializer`] methods to control the serialization process.
///
/// In order to process certain values (like unions or empty lists) correctly, it is necessary to
/// add a type annotation (with [`static_type_annotation()`] or [`type_annotation()`]).
///
/// # Examples
///
/// ```rust
/// # fn main() -> serde_dhall::Result<()> {
/// use serde::Serialize;
/// use serde_dhall::{serialize, StaticType};
///
/// #[derive(Serialize)]
/// struct Point {
/// x: u64,
/// y: u64,
/// }
///
///
/// let data = Point { x: 0, y: 0 };
/// let string = serialize(&data).to_string()?;
/// assert_eq!(string, "{ x = 0, y = 0 }");
/// # Ok(())
/// # }
/// ```
///
/// ```rust
/// # fn main() -> serde_dhall::Result<()> {
/// use serde::Serialize;
/// use serde_dhall::{serialize, StaticType};
///
/// #[derive(Serialize, StaticType)]
/// enum MyOption {
/// MyNone,
/// MySome(u64),
/// }
///
/// let data = MyOption::MySome(0);
/// let string = serialize(&data)
/// .static_type_annotation()
/// .to_string()?;
/// // The resulting Dhall string depends on the type annotation; it could not have been
/// // printed without it.
/// assert_eq!(string, "< MyNone | MySome: Natural >.MySome 0".to_string());
/// # Ok(())
/// # }
/// ```
///
/// [`type_annotation()`]: Serializer::type_annotation()
/// [`static_type_annotation()`]: Serializer::static_type_annotation()
/// [`to_string()`]: Serializer::to_string()
pub fn serialize<T>(data: &T) -> Serializer<'_, T, NoAnnot>
where
T: ToDhall,
{
Serializer {
data,
annot: NoAnnot,
}
}
|
