1use quote::ToTokens;
2use syn::{
3 spanned::Spanned, FnArg, GenericArgument, PatType, PathArguments, Result, Type, TypePath,
4};
5
6pub fn parse_args(iter: impl IntoIterator<Item = FnArg>) -> Result<Vec<ArgInfo>> {
7 let mut args = Vec::new();
8 for (n, arg) in iter.into_iter().enumerate() {
9 if let FnArg::Receiver(_) = arg {
10 continue;
11 }
12 let arg = ArgInfo::try_from(arg)?;
13 if let Type::Path(TypePath { path, .. }) = &arg.r#type {
14 let last = path.segments.last().unwrap();
15 if last.ident == "Python" {
16 continue;
17 }
18 // Regard the first argument with `PyRef<'_, Self>` and `PyMutRef<'_, Self>` types as a receiver.
19 if n == 0 && (last.ident == "PyRef" || last.ident == "PyRefMut") {
20 if let PathArguments::AngleBracketed(inner) = &last.arguments {
21 if let GenericArgument::Type(Type::Path(TypePath { path, .. })) =
22 &inner.args[inner.args.len() - 1]
23 {
24 let last = path.segments.last().unwrap();
25 if last.ident == "Self" {
26 continue;
27 }
28 }
29 }
30 }
31 }
32 args.push(arg);
33 }
34 Ok(args)
35}
36
37#[derive(Debug)]
38pub struct ArgInfo {
39 pub name: String,
40 pub r#type: Type,
41}
42
43impl TryFrom<FnArg> for ArgInfo {
44 type Error = syn::Error;
45 fn try_from(value: FnArg) -> Result<Self> {
46 let span: Span = value.span();
47 if let FnArg::Typed(PatType { pat: Box, ty: Box, .. }) = value {
48 if let syn::Pat::Ident(mut ident: PatIdent) = *pat {
49 ident.mutability = None;
50 let name: String = ident.to_token_stream().to_string();
51 return Ok(Self { name, r#type: *ty });
52 }
53 }
54 Err(syn::Error::new(span, message:"Expected typed argument"))
55 }
56}
57