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#![recursion_limit = "128"]
extern crate proc_macro;
use proc_macro2;
use quote::quote;
use syn;
use proc_macro::TokenStream;
#[proc_macro_derive(Validate)]
pub fn main(input: TokenStream) -> TokenStream {
let ast = syn::parse(input).unwrap();
let tokens = expand(&ast);
tokens.into()
}
fn expand(ast: &syn::DeriveInput) -> proc_macro2::TokenStream {
let fields = match ast.data {
syn::Data::Struct(syn::DataStruct { ref fields, .. }) => fields,
_ => panic!("#[derive(Validate)] only works on `struct`s"),
};
let ident = &ast.ident;
let minimal_validations: Vec<_> = fields
.iter()
.map(|f| f.ident.as_ref().unwrap())
.map(|ident| {
use inflections::Inflect;
let field = ident.to_string().to_camel_case();
quote!(
self.#ident.validate_minimally(
_root,
|| _path().field(#field),
_report,
)
)
})
.collect();
let complete_validations: Vec<_> = fields
.iter()
.map(|f| f.ident.as_ref().unwrap())
.map(|ident| {
use inflections::Inflect;
let field = ident.to_string().to_camel_case();
quote!(
self.#ident.validate_completely(
_root,
|| _path().field(#field),
_report,
)
)
})
.collect();
let (impl_generics, ty_generics, where_clause) = ast.generics.split_for_impl();
quote!(
impl #impl_generics crate::validation::Validate
for #ident #ty_generics #where_clause
{
fn validate_minimally<P, R>(
&self,
_root: &crate::Root,
_path: P,
_report: &mut R
) where
P: Fn() -> crate::Path,
R: FnMut(&Fn() -> crate::Path, crate::validation::Error),
{
#(
#minimal_validations;
)*
}
fn validate_completely<P, R>(
&self,
_root: &crate::Root,
_path: P,
_report: &mut R
) where
P: Fn() -> crate::Path,
R: FnMut(&Fn() -> crate::Path, crate::validation::Error),
{
#(
#complete_validations;
)*
}
}
)
}