use proc_macro::TokenStream;
use proc_macro2::{Ident, Span};
use quote::quote;
use syn::DeriveInput;
pub fn impl_big_int_u64(ast: &DeriveInput) -> TokenStream {
impl_big_int(ast, &Ident::new("u64", Span::call_site()))
}
pub fn impl_big_int_usize(ast: &DeriveInput) -> TokenStream {
impl_big_int(ast, &Ident::new("usize", Span::call_site()))
}
fn impl_big_int(ast: &DeriveInput, int: &Ident) -> TokenStream {
let name = &ast.ident;
let stream = quote! {
impl serde::Serialize for #name {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: serde::Serializer,
{
serializer.serialize_str(self.0.to_string().as_str())
}
}
impl<'de> serde::Deserialize<'de> for #name {
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
D: serde::Deserializer<'de>,
{
use serde::de::Error as _;
String::deserialize(deserializer)?
.parse::<#int>()
.map(Self)
.map_err(D::Error::custom)
}
}
};
stream.into()
}