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#![allow(unused)]
extern crate proc_macro;
use quote::quote;
use syn::{
Data,
DataStruct,
Fields,
Field,
Variant,
FieldsUnnamed,
};
use generic_core::into::*;
use generic_core::value::*;
#[proc_macro_derive(IntoGeneric)]
pub fn into_generic_derive(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
let ast = syn::parse::<syn::DeriveInput>(input).expect("syn::parse failed");
let type_name = ast.ident.clone();
match ast.data.clone() {
Data::Struct(DataStruct{fields: Fields::Named(named), ..}) => {
let fields = named.named.into_iter().collect::<Vec<_>>();
into_generic_struct(&type_name, &fields)
}
Data::Struct(DataStruct{fields: Fields::Unnamed(xs), ..}) => {
into_generic_tuple_struct(&type_name, xs)
}
Data::Struct(DataStruct{fields: Fields::Unit, ..}) => {
unimplemented!("Unit structs not yet supported")
}
Data::Enum(xs) => {
let variants = xs.variants
.into_iter()
.collect::<Vec<_>>();
into_generic_enum(&type_name, &variants)
}
Data::Union(_) => {
unimplemented!("Union types not yet supported")
}
}
}
fn into_generic_struct(type_name: &proc_macro2::Ident, fields: &[Field]) -> proc_macro::TokenStream {
let field_conversions = fields
.iter()
.map(|field| {
let field_ident = field.ident
.clone()
.expect("missing ident");
quote! {
let key = stringify!(#field_ident).to_owned();
let value = IntoGeneric::into_generic(&self.#field_ident);
map.insert(key, value);
}
})
.collect::<Vec<_>>();
let gen = quote! {
impl IntoGeneric for #type_name {
fn into_generic(&self) -> Value {
use generic_core::into::*;
use generic_core::value::*;
let mut map: HashMap<String, Value> = std::collections::HashMap::new();
#(#field_conversions)*
Value::Struct(Struct {
type_name: String::from(stringify!(#type_name)),
data: map,
})
}
}
};
gen.into()
}
fn into_generic_tuple_struct(type_name: &proc_macro2::Ident, fields: FieldsUnnamed) -> proc_macro::TokenStream {
let field_conversions = fields.unnamed
.iter()
.enumerate()
.map(|(ix, _)| {
let ix = syn::Index::from(ix);
quote!{
let value = IntoGeneric::into_generic(&self.#ix);
vec.push(value);
}
})
.collect::<Vec<_>>();
let gen = quote! {
impl IntoGeneric for #type_name {
fn into_generic(&self) -> Value {
use generic_core::into::*;
use generic_core::value::*;
let mut vec = Vec::<Value>::new();
#(#field_conversions)*
Value::TupleStruct(TupleStruct {
type_name: String::from(stringify!(#type_name)),
data: vec,
})
}
}
};
gen.into()
}
fn into_generic_enum(type_name: &proc_macro2::Ident, variants: &[Variant]) -> proc_macro::TokenStream {
let arms = variants
.iter()
.map(|var| {
let variant_name = &var.ident;
match var.fields.clone() {
Fields::Named(xs) => {
let (ident_binders, to_generics) = xs.named
.iter()
.map(|x| {
let ident = x.ident.clone().expect("todo - tuple structs");
let binder = quote!{
ref #ident,
};
let to_generic = quote!{
let key = stringify!(#ident).to_owned();
let value = IntoGeneric::into_generic(#ident);
map.insert(key, value);
};
(binder, to_generic)
})
.unzip::<_, _, Vec<_>, Vec<_>>();
quote! {
#type_name::#variant_name{#(#ident_binders)*} => {
let mut map = std::collections::HashMap::<String, Value>::new();
#(#to_generics)*
Value::Variant(Variant::StructVariant {
type_name: stringify!(#type_name).to_owned(),
variant_name: stringify!(#variant_name).to_owned(),
data: map,
})
}
}
},
Fields::Unnamed(xs) => {
let (ident_binders, to_generics) = xs.unnamed
.iter()
.map(|_| {
let ident = format!("id_{}", rand::random::<u16>());
let ident = proc_macro2::Ident::new(&ident, proc_macro2::Span::call_site());
let binder = quote!{
ref #ident,
};
let to_generic = quote!{
let value = IntoGeneric::into_generic(#ident);
vec.push(value);
};
(binder, to_generic)
})
.unzip::<_, _, Vec<_>, Vec<_>>();
quote! {
#type_name::#variant_name(#(#ident_binders)*) => {
let mut vec = Vec::<Value>::new();
#(#to_generics)*
Value::Variant(Variant::TupleVariant {
type_name: stringify!(#type_name).to_owned(),
variant_name: stringify!(#variant_name).to_owned(),
data: vec,
})
}
}
},
Fields::Unit => {
quote! {
#type_name::#variant_name => {
Value::Variant(Variant::UnitVariant{
type_name: stringify!(#type_name).to_owned(),
variant_name: stringify!(#variant_name).to_owned(),
})
}
}
},
}
});
let gen = quote! {
impl IntoGeneric for #type_name {
fn into_generic(&self) -> Value {
use generic_core::into::*;
use generic_core::value::*;
match self {
#(#arms)*
}
}
}
};
gen.into()
}