wasmi/derive/src/parser.rs

50 lines
1.6 KiB
Rust

use crate::model::{self, ExtDefinition, ExternalFunc, Param};
use syn::{ItemImpl, ImplItem, ImplItemMethod, FnArg, ReturnType, Ident};
use syn::spanned::Spanned;
/// Parse an incoming stream of tokens into externalities definition.
pub fn parse(input: proc_macro2::TokenStream) -> Result<ExtDefinition, ()> {
let item_impl = syn::parse2::<syn::ItemImpl>(input).map_err(|_| ())?;
let mut funcs = vec![];
for item in item_impl.items {
match item {
ImplItem::Method(ImplItemMethod {
sig,
..
}) => {
let index = funcs.len() as u32;
// self TODO: handle this properly
let args = sig.decl.inputs.iter().skip(1).enumerate().map(|(idx, input)| {
let param_name = format!("arg{}", idx);
let ident = Ident::new(&param_name, input.span());
Param {
ident,
}
}).collect::<Vec<_>>();
let return_ty = match sig.decl.output {
ReturnType::Default => None,
ReturnType::Type(_, ty) => Some(ty.span()),
};
funcs.push(ExternalFunc {
index,
name: sig.ident.to_string(),
args,
return_ty,
});
},
_ => {},
}
}
Ok(ExtDefinition {
funcs,
generics: item_impl.generics.clone(),
ty: item_impl.self_ty.clone(),
})
}