sqlxgentools/lib/sqlxgentools_attrs/src/lib.rs

use proc_macro::TokenStream;
use quote::quote;
use syn::{DeriveInput, Fields, parse_macro_input};

#[proc_macro_attribute]
pub fn sql_generator_model(_attr: TokenStream, item: TokenStream) -> TokenStream {
    item
}

#[proc_macro_derive(SqlGeneratorDerive, attributes(sql_generator_field))]
pub fn derive_sql_generator_model(_input: TokenStream) -> TokenStream {
    TokenStream::new()
}

#[proc_macro_derive(SqlGeneratorModelWithId, attributes(sql_generator_field))]
pub fn derive_sql_generator_model_with_id(input: TokenStream) -> TokenStream {
    let input = parse_macro_input!(input as DeriveInput);
    let name = input.ident;

    // Extract the fields of the struct
    if let syn::Data::Struct(data) = input.data {
        if let Fields::Named(fields) = data.fields {
            for field in fields.named {
                if field.ident.as_ref().map_or(false, |ident| ident == "id") {
                    let expanded = quote! {
                        impl DatabaseLine for #name {
                            fn id(&self) -> String {
                                self.id.clone()
                            }
                        }
                    };
                    return TokenStream::from(expanded);
                }
            }
        }
    }

    // If `id` field is not found, return an error
    panic!("Expected struct with a named field `id` of type String")
}