86 lines
2.7 KiB
Rust
86 lines
2.7 KiB
Rust
use crate::helper_structs::AttrInnerKeyStringMap;
|
|
use crate::helpers::{fold_error_iter, two_segment_path};
|
|
use proc_macro2::{Span, TokenStream as TokenStream2};
|
|
use syn::{Attribute, Data, DeriveInput, LitStr, Variant};
|
|
|
|
fn parse_hint_helper_attrs(attrs: &[Attribute]) -> syn::Result<(Vec<LitStr>, Vec<LitStr>)> {
|
|
fold_error_iter(
|
|
attrs
|
|
.iter()
|
|
.filter(|a| a.path().get_ident().is_some_and(|i| i == "hint"))
|
|
.map(|attr| attr.parse_args::<AttrInnerKeyStringMap>()),
|
|
)
|
|
.and_then(|v: Vec<AttrInnerKeyStringMap>| {
|
|
fold_error_iter(AttrInnerKeyStringMap::multi_into_iter(v).map(|(k, mut v)| match v.len() {
|
|
0 => panic!("internal error: a key without values was somehow inserted into the hashmap"),
|
|
1 => {
|
|
let single_val = v.pop().unwrap();
|
|
Ok((LitStr::new(&k.to_string(), Span::call_site()), single_val))
|
|
}
|
|
_ => {
|
|
// the first value is ok, the other ones should error
|
|
let after_first = v.into_iter().skip(1);
|
|
// this call to fold_error_iter will always return Err with a combined error
|
|
fold_error_iter(after_first.map(|lit| Err(syn::Error::new(lit.span(), format!("value for key {k} was already given"))))).map(|_: Vec<()>| unreachable!())
|
|
}
|
|
}))
|
|
})
|
|
.map(|v| v.into_iter().unzip())
|
|
}
|
|
|
|
pub fn derive_hint_impl(input_item: TokenStream2) -> syn::Result<TokenStream2> {
|
|
let input = syn::parse2::<DeriveInput>(input_item)?;
|
|
|
|
let ident = input.ident;
|
|
|
|
match input.data {
|
|
Data::Enum(data) => {
|
|
let variants = data.variants.iter().map(|var: &Variant| two_segment_path(ident.clone(), var.ident.clone())).collect::<Vec<_>>();
|
|
|
|
let hint_result = fold_error_iter(data.variants.into_iter().map(|var: Variant| parse_hint_helper_attrs(&var.attrs)));
|
|
|
|
hint_result.map(|hints: Vec<(Vec<LitStr>, Vec<LitStr>)>| {
|
|
let (keys, values): (Vec<Vec<LitStr>>, Vec<Vec<LitStr>>) = hints.into_iter().unzip();
|
|
let cap: Vec<usize> = keys.iter().map(|v| v.len()).collect();
|
|
|
|
quote::quote! {
|
|
impl Hint for #ident {
|
|
fn hints(&self) -> ::std::collections::HashMap<String, String> {
|
|
match self {
|
|
#(
|
|
#variants { .. } => {
|
|
let mut hm = ::std::collections::HashMap::with_capacity(#cap);
|
|
#(
|
|
hm.insert(#keys.to_string(), #values.to_string());
|
|
)*
|
|
hm
|
|
}
|
|
)*
|
|
}
|
|
}
|
|
}
|
|
}
|
|
})
|
|
}
|
|
Data::Struct(_) | Data::Union(_) => {
|
|
let hint_result = parse_hint_helper_attrs(&input.attrs);
|
|
|
|
hint_result.map(|(keys, values)| {
|
|
let cap = keys.len();
|
|
|
|
quote::quote! {
|
|
impl Hint for #ident {
|
|
fn hints(&self) -> ::std::collections::HashMap<String, String> {
|
|
let mut hm = ::std::collections::HashMap::with_capacity(#cap);
|
|
#(
|
|
hm.insert(#keys.to_string(), #values.to_string());
|
|
)*
|
|
hm
|
|
}
|
|
}
|
|
}
|
|
})
|
|
}
|
|
}
|
|
}
|