Graphite/node-graph/proc-macro/src/lib.rs

99 lines
2.9 KiB
Rust

use proc_macro::TokenStream;
use proc_macro_roids::*;
use quote::{quote, ToTokens};
use syn::punctuated::Punctuated;
use syn::{parse_macro_input, FnArg, ItemFn, Pat, Type};
fn extract_type(a: FnArg) -> Type {
match a {
FnArg::Typed(p) => *p.ty, // notice `ty` instead of `pat`
_ => panic!("Not supported on types with `self`!"),
}
}
fn extract_arg_types(fn_args: Punctuated<FnArg, syn::token::Comma>) -> Vec<Type> {
fn_args.into_iter().map(extract_type).collect::<Vec<_>>()
}
fn extract_arg_idents(fn_args: Punctuated<FnArg, syn::token::Comma>) -> Vec<Pat> {
fn_args.into_iter().map(extract_arg_pat).collect::<Vec<_>>()
}
fn extract_arg_pat(a: FnArg) -> Pat {
match a {
FnArg::Typed(p) => *p.pat,
_ => panic!("Not supported on types with `self`!"),
}
}
#[proc_macro_attribute] // 2
pub fn to_node(_attr: TokenStream, item: TokenStream) -> TokenStream {
let string = item.to_string();
let item2 = item;
let parsed = parse_macro_input!(item2 as ItemFn); // 3
//item.extend(generate_to_string(parsed, string)); // 4
//item
generate_to_string(parsed, string)
}
fn generate_to_string(parsed: ItemFn, string: String) -> TokenStream {
let whole_function = parsed.clone();
//let fn_body = parsed.block; // function body
let sig = parsed.sig; // function signature
//let vis = parsed.vis; // visibility, pub or not
let generics = sig.generics;
let fn_args = sig.inputs; // comma separated args
let fn_return_type = sig.output; // return type
let fn_name = sig.ident; // function name/identifier
let idents = extract_arg_idents(fn_args.clone());
let types = extract_arg_types(fn_args);
let types = types.iter().map(|t| t.to_token_stream()).collect::<Vec<_>>();
let idents = idents.iter().map(|t| t.to_token_stream()).collect::<Vec<_>>();
let _const_idents = idents
.iter()
.map(|t| {
let name = t.to_string().to_uppercase();
quote! {#name}
})
.collect::<Vec<_>>();
let node_fn_name = fn_name.append("_node");
let struct_name = fn_name.append("_input");
let return_type_string = fn_return_type.to_token_stream().to_string().replace("->", "");
let arg_type_string = types.iter().map(|t| t.to_string()).collect::<Vec<_>>().join(", ");
let error = format!("called {} with the wrong type", fn_name);
let x = quote! {
//#whole_function
mod #fn_name {
#[derive(Copy, Clone)]
type F32Node<'n> = &'n (dyn Node<'n, (), Output = &'n (dyn Any + 'static)> + 'n);
struct #struct_name {
#(#idents: #types,)*
}
impl Node for #struct_name {
}
}
fn #node_fn_name #generics() -> Node<'static> {
Node { func: Box::new(move |x| {
let args = x.downcast::<(#(#types,)*)>().expect(#error);
let (#(#idents,)*) = *args;
#whole_function
Box::new(#fn_name(#(#idents,)*))
}),
code: #string.to_string(),
return_type: #return_type_string.trim().to_string(),
args: format!("({})",#arg_type_string.trim()),
position: (0., 0.),
}
}
};
//panic!("{}\n{:?}", x.to_string(), x);
x.into()
}