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Diffstat (limited to 'serde_dhall/src/options/ser.rs')
| -rw-r--r-- | serde_dhall/src/options/ser.rs | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/serde_dhall/src/options/ser.rs b/serde_dhall/src/options/ser.rs new file mode 100644 index 0000000..d74beb0 --- /dev/null +++ b/serde_dhall/src/options/ser.rs @@ -0,0 +1,234 @@ +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<String>`] 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. +/// +/// [`Serializer`]: struct.Serializer.html +/// [`serialize`]: fn.serialize.html +/// [`to_string`]: struct.Serializer.html#method.to_string +/// [`Result<String>`]: type.Result.html +/// +/// # 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(()) + /// # } + /// ``` + /// + /// [`static_type_annotation`]: struct.Serializer.html#method.static_type_annotation + /// [`StaticType`]: trait.StaticType.html + 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(()) + /// # } + /// ``` + /// + /// [`type_annotation`]: struct.Serializer.html#method.type_annotation + /// [`StaticType`]: trait.StaticType.html + 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`]: trait.StaticType.html + 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(()) +/// # } +/// ``` +/// +/// [`Serializer`]: struct.Serializer.html +/// [`type_annotation`]: struct.Serializer.html#method.type_annotation +/// [`static_type_annotation`]: struct.Serializer.html#method.static_type_annotation +/// [`to_string`]: struct.Serializer.html#method.to_string +pub fn serialize<T>(data: &T) -> Serializer<'_, T, NoAnnot> +where + T: ToDhall, +{ + Serializer { + data, + annot: NoAnnot, + } +} |