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Diffstat (limited to 'serde_dhall/src/options.rs')
| -rw-r--r-- | serde_dhall/src/options.rs | 368 |
1 files changed, 368 insertions, 0 deletions
diff --git a/serde_dhall/src/options.rs b/serde_dhall/src/options.rs new file mode 100644 index 0000000..06a4368 --- /dev/null +++ b/serde_dhall/src/options.rs @@ -0,0 +1,368 @@ +use std::path::{Path, PathBuf}; + +use dhall::Parsed; + +use crate::SimpleType; +use crate::{Error, ErrorKind, FromDhall, Result, StaticType, Value}; + +#[derive(Debug, Clone)] +enum Source<'a> { + Str(&'a str), + File(PathBuf), + // Url(&'a str), +} + +#[derive(Debug, Clone, Copy)] +pub struct NoAnnot; +#[derive(Debug, Clone, Copy)] +pub struct ManualAnnot<'ty>(&'ty SimpleType); +#[derive(Debug, Clone, Copy)] +pub struct StaticAnnot; + +pub trait HasAnnot<A> { + fn get_annot(a: &A) -> Option<SimpleType>; +} +impl<T> HasAnnot<NoAnnot> for T { + fn get_annot(_: &NoAnnot) -> Option<SimpleType> { + None + } +} +impl<'ty, T> HasAnnot<ManualAnnot<'ty>> for T { + fn get_annot(a: &ManualAnnot<'ty>) -> Option<SimpleType> { + Some(a.0.clone()) + } +} +impl<T: StaticType> HasAnnot<StaticAnnot> for T { + fn get_annot(_: &StaticAnnot) -> Option<SimpleType> { + Some(T::static_type()) + } +} + +/// Controls how a Dhall value is read. +/// +/// This builder exposes the ability to configure how a value is deserialized and what operations +/// are permitted during evaluation. +/// +/// Generally speaking, when using [`Deserializer`], you'll create it with [`from_str`] or [`from_file`], then +/// chain calls to methods to set each option, then call [`parse`]. This will give you a +/// [`Result<T>`] where `T` is a deserializable type of your choice. +/// +/// [`Deserializer`]: struct.Deserializer.html +/// [`from_str`]: fn.from_str.html +/// [`from_file`]: fn.from_file.html +/// [`parse`]: struct.Deserializer.html#method.parse +/// [`Result<T>`]: type.Result.html +/// +/// # Examples +/// +/// Reading from a file: +/// +/// ```no_run +/// # fn main() -> serde_dhall::Result<()> { +/// use serde_dhall::from_file; +/// +/// let data = from_file("foo.dhall").parse::<u64>()?; +/// # Ok(()) +/// # } +/// ``` +/// +/// Reading from a file and checking the value against a provided type: +/// +/// ```no_run +/// # fn main() -> serde_dhall::Result<()> { +/// use std::collections::HashMap; +/// use serde_dhall::{from_file, from_str}; +/// +/// let ty = from_str("{ x: Natural, y: Natural }").parse()?; +/// let data = from_file("foo.dhall") +/// .type_annotation(&ty) +/// .parse::<HashMap<String, usize>>()?; +/// # Ok(()) +/// # } +/// ``` +#[derive(Debug, Clone)] +pub struct Deserializer<'a, A> { + source: Source<'a>, + annot: A, + allow_imports: bool, + // allow_remote_imports: bool, + // use_cache: bool, +} + +impl<'a> Deserializer<'a, NoAnnot> { + fn default_with_source(source: Source<'a>) -> Self { + Deserializer { + source, + annot: NoAnnot, + allow_imports: true, + // allow_remote_imports: true, + // use_cache: true, + } + } + fn from_str(s: &'a str) -> Self { + Self::default_with_source(Source::Str(s)) + } + fn from_file<P: AsRef<Path>>(path: P) -> Self { + Self::default_with_source(Source::File(path.as_ref().to_owned())) + } + // fn from_url(url: &'a str) -> Self { + // Self::default_with_source(Source::Url(url)) + // } + + /// Ensures that the parsed value matches the provided type. + /// + /// 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 std::collections::HashMap; + /// use serde::Deserialize; + /// use serde_dhall::{from_str, SimpleType}; + /// + /// // Parse a Dhall type + /// let type_str = "{ x: Natural, y: Natural }"; + /// let ty = from_str(type_str).parse::<SimpleType>()?; + /// + /// // Parse some Dhall data. + /// let data = "{ x = 1, y = 1 + 1 }"; + /// let point = from_str(data) + /// .type_annotation(&ty) + /// .parse::<HashMap<String, usize>>()?; + /// assert_eq!(point.get("y"), Some(&2)); + /// + /// // Invalid data fails the type validation; deserialization would have succeeded otherwise. + /// let invalid_data = "{ x = 1, z = 3 }"; + /// assert!( + /// from_str(invalid_data) + /// .type_annotation(&ty) + /// .parse::<HashMap<String, usize>>() + /// .is_err() + /// ); + /// # Ok(()) + /// # } + /// ``` + /// + /// [`static_type_annotation`]: struct.Deserializer.html#method.static_type_annotation + /// [`StaticType`]: trait.StaticType.html + pub fn type_annotation<'ty>( + self, + ty: &'ty SimpleType, + ) -> Deserializer<'a, ManualAnnot<'ty>> { + Deserializer { + annot: ManualAnnot(ty), + source: self.source, + allow_imports: self.allow_imports, + } + } + + /// Ensures that the parsed value matches the type of `T`. + /// + /// `T` must implement the [`StaticType`] trait. If it doesn't, you can use [`type_annotation`] + /// to provide a type manually. + /// + /// # Example + /// + /// ``` + /// # fn main() -> serde_dhall::Result<()> { + /// use serde::Deserialize; + /// use serde_dhall::StaticType; + /// + /// #[derive(Deserialize, StaticType)] + /// struct Point { + /// x: u64, + /// y: Option<u64>, + /// } + /// + /// // Some Dhall data + /// let data = "{ x = 1, y = Some (1 + 1) }"; + /// + /// // Convert the Dhall string to a Point. + /// let point = serde_dhall::from_str(data) + /// .static_type_annotation() + /// .parse::<Point>()?; + /// assert_eq!(point.x, 1); + /// assert_eq!(point.y, Some(2)); + /// + /// // Invalid data fails the type validation; deserialization would have succeeded otherwise. + /// let invalid_data = "{ x = 1 }"; + /// assert!( + /// serde_dhall::from_str(invalid_data) + /// .static_type_annotation() + /// .parse::<Point>() + /// .is_err() + /// ); + /// # Ok(()) + /// # } + /// ``` + /// + /// [`type_annotation`]: struct.Deserializer.html#method.type_annotation + /// [`StaticType`]: trait.StaticType.html + pub fn static_type_annotation(self) -> Deserializer<'a, StaticAnnot> { + Deserializer { + annot: StaticAnnot, + source: self.source, + allow_imports: self.allow_imports, + } + } +} + +impl<'a, A> Deserializer<'a, A> { + /// Sets whether to enable imports. + /// + /// By default, imports are enabled. + /// + /// # Example + /// + /// ``` + /// # fn main() -> serde_dhall::Result<()> { + /// use serde::Deserialize; + /// use serde_dhall::SimpleType; + /// + /// let data = "12 + ./other_file.dhall : Natural"; + /// assert!( + /// serde_dhall::from_str(data) + /// .imports(false) + /// .parse::<u64>() + /// .is_err() + /// ); + /// # Ok(()) + /// # } + /// ``` + /// + /// [`static_type_annotation`]: struct.Deserializer.html#method.static_type_annotation + /// [`StaticType`]: trait.StaticType.html + pub fn imports(self, imports: bool) -> Self { + Deserializer { + allow_imports: imports, + ..self + } + } + + // /// TODO + // pub fn remote_imports(&mut self, imports: bool) -> &mut Self { + // self.allow_remote_imports = imports; + // if imports { + // self.allow_imports = true; + // } + // self + // } + + fn _parse<T>(&self) -> dhall::error::Result<Value> + where + T: HasAnnot<A>, + { + let parsed = match &self.source { + Source::Str(s) => Parsed::parse_str(s)?, + Source::File(p) => Parsed::parse_file(p.as_ref())?, + }; + let resolved = if self.allow_imports { + parsed.resolve()? + } else { + parsed.skip_resolve()? + }; + let typed = match &T::get_annot(&self.annot) { + None => resolved.typecheck()?, + Some(ty) => resolved.typecheck_with(ty.to_value().as_hir())?, + }; + Ok(Value::from_nir(typed.normalize().as_nir())) + } + + /// Parses the chosen dhall value with the options provided. + /// + /// If you enabled static annotations, `T` is required to implement [`StaticType`]. + /// + /// + /// # Example + /// + /// ``` + /// # fn main() -> serde_dhall::Result<()> { + /// let data = serde_dhall::from_str("6 * 7").parse::<u64>()?; + /// assert_eq!(data, 42); + /// # Ok(()) + /// # } + /// ``` + /// [`StaticType`]: trait.StaticType.html + pub fn parse<T>(&self) -> Result<T> + where + T: FromDhall + HasAnnot<A>, + { + let val = self + ._parse::<T>() + .map_err(ErrorKind::Dhall) + .map_err(Error)?; + T::from_dhall(&val) + } +} + +/// Deserialize a value from a string of Dhall text. +/// +/// This returns a [`Deserializer`] object. Call the [`parse`] method to get the deserialized +/// value, or use other [`Deserializer`] methods to control the deserialization process. +/// +/// # Example +/// +/// ```rust +/// # fn main() -> serde_dhall::Result<()> { +/// use serde::Deserialize; +/// +/// // We use serde's derive feature +/// #[derive(Deserialize)] +/// struct Point { +/// x: u64, +/// y: u64, +/// } +/// +/// // Some Dhall data +/// let data = "{ x = 1, y = 1 + 1 } : { x: Natural, y: Natural }"; +/// +/// // Parse the Dhall string as a Point. +/// let point: Point = serde_dhall::from_str(data).parse()?; +/// +/// assert_eq!(point.x, 1); +/// assert_eq!(point.y, 2); +/// # Ok(()) +/// # } +/// ``` +/// +/// [`Deserializer`]: struct.Deserializer.html +/// [`parse`]: struct.Deserializer.html#method.parse +pub fn from_str(s: &str) -> Deserializer<'_, NoAnnot> { + Deserializer::from_str(s) +} + +/// Deserialize a value from a Dhall file. +/// +/// This returns a [`Deserializer`] object. Call the [`parse`] method to get the deserialized +/// value, or use other [`Deserializer`] methods to control the deserialization process. +/// +/// # Example +/// +/// ```no_run +/// # fn main() -> serde_dhall::Result<()> { +/// use serde::Deserialize; +/// +/// // We use serde's derive feature +/// #[derive(Deserialize)] +/// struct Point { +/// x: u64, +/// y: u64, +/// } +/// +/// // Parse the Dhall file as a Point. +/// let point: Point = serde_dhall::from_file("foo.dhall").parse()?; +/// # Ok(()) +/// # } +/// ``` +/// +/// [`Deserializer`]: struct.Deserializer.html +/// [`parse`]: struct.Deserializer.html#method.parse +pub fn from_file<'a, P: AsRef<Path>>(path: P) -> Deserializer<'a, NoAnnot> { + Deserializer::from_file(path) +} + +// pub fn from_url(url: &str) -> Deserializer<'_, NoAnnot> { +// Deserializer::from_url(url) +// } |