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|
use std::borrow::Cow;
use serde::de::value::{
MapAccessDeserializer, MapDeserializer, SeqDeserializer,
};
use dhall::syntax::{ExprKind, LitKind};
use dhall::NormalizedExpr;
use crate::de::{Deserialize, Error, Result};
use crate::Value;
impl<'a, T> crate::de::sealed::Sealed for T where T: serde::Deserialize<'a> {}
impl<'a, T> Deserialize for T
where
T: serde::Deserialize<'a>,
{
fn from_dhall(v: &Value) -> Result<Self> {
T::deserialize(Deserializer(Cow::Owned(v.to_expr())))
}
}
struct Deserializer<'a>(Cow<'a, NormalizedExpr>);
impl<'de: 'a, 'a> serde::de::IntoDeserializer<'de, Error> for Deserializer<'a> {
type Deserializer = Deserializer<'a>;
fn into_deserializer(self) -> Self::Deserializer {
self
}
}
impl<'de: 'a, 'a> serde::Deserializer<'de> for Deserializer<'a> {
type Error = Error;
fn deserialize_any<V>(self, visitor: V) -> Result<V::Value>
where
V: serde::de::Visitor<'de>,
{
use std::convert::TryInto;
use ExprKind::*;
use LitKind::*;
let expr = self.0.as_ref();
let not_serde_compatible = || {
Err(Error::Deserialize(format!(
"this cannot be deserialized into the serde data model: {}",
expr
)))
};
match expr.kind() {
Lit(Bool(x)) => visitor.visit_bool(*x),
Lit(Natural(x)) => {
if let Ok(x64) = (*x).try_into() {
visitor.visit_u64(x64)
} else if let Ok(x32) = (*x).try_into() {
visitor.visit_u32(x32)
} else {
unimplemented!()
}
}
Lit(Integer(x)) => {
if let Ok(x64) = (*x).try_into() {
visitor.visit_i64(x64)
} else if let Ok(x32) = (*x).try_into() {
visitor.visit_i32(x32)
} else {
unimplemented!()
}
}
Lit(Double(x)) => visitor.visit_f64((*x).into()),
TextLit(x) => {
// Normal form ensures that the tail is empty.
assert!(x.tail().is_empty());
visitor.visit_str(x.head())
}
EmptyListLit(..) => {
visitor.visit_seq(SeqDeserializer::new(None::<()>.into_iter()))
}
NEListLit(xs) => visitor.visit_seq(SeqDeserializer::new(
xs.iter().map(|x| Deserializer(Cow::Borrowed(x))),
)),
SomeLit(x) => visitor.visit_some(Deserializer(Cow::Borrowed(x))),
App(f, x) => match f.kind() {
Builtin(dhall::syntax::Builtin::OptionalNone) => {
visitor.visit_none()
}
Field(y, name) => match y.kind() {
UnionType(..) => {
let name: String = name.into();
visitor.visit_enum(MapAccessDeserializer::new(
MapDeserializer::new(
Some((name, Deserializer(Cow::Borrowed(x))))
.into_iter(),
),
))
}
_ => not_serde_compatible(),
},
_ => not_serde_compatible(),
},
RecordLit(m) => visitor
.visit_map(MapDeserializer::new(m.iter().map(|(k, v)| {
(k.as_ref(), Deserializer(Cow::Borrowed(v)))
}))),
Field(y, name) => match y.kind() {
UnionType(..) => {
let name: String = name.into();
visitor.visit_enum(MapAccessDeserializer::new(
MapDeserializer::new(Some((name, ())).into_iter()),
))
}
_ => not_serde_compatible(),
},
Const(..) | Var(..) | Lam(..) | Pi(..) | Let(..) | Annot(..)
| Assert(..) | Builtin(..) | BinOp(..) | BoolIf(..)
| RecordType(..) | UnionType(..) | Merge(..) | ToMap(..)
| Projection(..) | ProjectionByExpr(..) | Completion(..)
| Import(..) => not_serde_compatible(),
}
}
fn deserialize_tuple<V>(self, _: usize, visitor: V) -> Result<V::Value>
where
V: serde::de::Visitor<'de>,
{
use ExprKind::*;
let expr = self.0.as_ref();
match expr.kind() {
// Blindly takes keys in sorted order.
RecordLit(m) => visitor.visit_seq(SeqDeserializer::new(
m.iter().map(|(_, v)| Deserializer(Cow::Borrowed(v))),
)),
_ => self.deserialize_any(visitor),
}
}
serde::forward_to_deserialize_any! {
bool i8 i16 i32 i64 i128 u8 u16 u32 u64 u128 f32 f64 char str string
bytes byte_buf option unit unit_struct newtype_struct seq
tuple_struct map struct enum identifier ignored_any
}
}
|
