preserves/implementations/rust/preserves/src/symbol.rs

66 lines
1.8 KiB
Rust

//! Serde support for serializing Rust data as Preserves symbols.
//!
//! Serde doesn't include symbols in its data model, so we do some somewhat awful tricks to
//! force things to come out the way we want them.
//!
//! # Example
//!
//! Either use [Symbol] directly in your data types, or annotate [String]-valued fields that
//! you want to (en|de)code as Preserves `Symbol`s with `#[serde(with = "preserves::symbol")]`:
//!
//! ```rust
//! #[derive(serde::Serialize, serde::Deserialize)]
//! struct Example {
//! sym1: preserves::symbol::Symbol,
//! #[serde(with = "preserves::symbol")]
//! sym2: String,
//! }
//! ```
use crate::value::{IOValue, NestedValue};
/// Wrapper for a string to coerce its Preserves-serialization to `Symbol`.
#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone)]
pub struct Symbol(pub String);
impl serde::Serialize for Symbol {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: serde::Serializer,
{
IOValue::symbol(&self.0).serialize(serializer)
}
}
impl<'de> serde::Deserialize<'de> for Symbol {
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
D: serde::Deserializer<'de>,
{
let v = IOValue::deserialize(deserializer)?;
let s = v
.value()
.as_symbol()
.ok_or_else(|| serde::de::Error::custom("Expected symbol"))?;
Ok(Symbol(s.clone()))
}
}
#[doc(hidden)]
pub fn serialize<S>(s: &str, serializer: S) -> Result<S::Ok, S::Error>
where
S: serde::Serializer,
{
use serde::Serialize;
Symbol(s.to_string()).serialize(serializer)
}
#[doc(hidden)]
pub fn deserialize<'de, D>(deserializer: D) -> Result<String, D::Error>
where
D: serde::Deserializer<'de>,
{
use serde::Deserialize;
Symbol::deserialize(deserializer).map(|v| v.0)
}