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use convert_case::{Case, Casing};
use proc_macro::TokenStream;
use syn::{parse_macro_input, spanned::Spanned, Data, DataStruct, DeriveInput, Fields, Ident};
extern crate proc_macro;
#[macro_use]
extern crate quote;
extern crate syn;
#[proc_macro_attribute]
pub fn auto_iden(_args: TokenStream, input: TokenStream) -> TokenStream {
let input = parse_macro_input!(input as DeriveInput);
let fields = match &input.data {
Data::Struct(DataStruct {
fields: Fields::Named(fields),
..
}) => &fields.named,
_ => panic!("#[auto_iden] can only be used on structs"),
};
let field_names = fields.iter().map(|field| {
let ident = &field.ident;
let str = ident
.as_ref()
.expect("#[auto_iden] can only be used on structs with named fields")
.to_string();
let to_pascal = str.to_case(Case::Pascal);
(ident.as_ref().unwrap(), Ident::new(to_pascal.as_str(), ident.span()))
});
let table_name = input.ident.to_string().to_case(Case::Snake);
let struct_name = quote::format_ident!("{}TypeDef", &input.ident);
let pascal_names = field_names.clone().map(|(_, pascal)| pascal);
let snake_names = field_names.map(|(snake, _)| snake);
let pascal_names2 = pascal_names.clone();
TokenStream::from(quote! {
#input
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
enum #struct_name {
Table,
#(#pascal_names),*
}
impl sea_query::Iden for #struct_name {
fn unquoted(&self, s: &mut dyn sea_query::Write) {
write!(s, "{}", match self {
#struct_name::Table => #table_name,
#(#struct_name::#pascal_names2 => stringify!(#snake_names)),*
}).unwrap();
}
}
})
}