yew_macro/derive_props/
generics.rs

1use proc_macro2::Ident;
2use syn::punctuated::Punctuated;
3use syn::{GenericArgument, GenericParam, Generics, Path, Token, Type, TypePath};
4
5/// Alias for a comma-separated list of `GenericArgument`
6pub type GenericArguments = Punctuated<GenericArgument, Token![,]>;
7
8/// Finds the index of the first generic param with a default value or a const generic.
9fn first_default_or_const_param_position(generics: &Generics) -> Option<usize> {
10    generics.params.iter().position(|param| match param {
11        GenericParam::Type(param) => param.default.is_some(),
12        GenericParam::Const(_) => true,
13        _ => false,
14    })
15}
16
17/// Push a type GenericParam into a Generics
18pub fn push_type_param(generics: &mut Generics, type_param: GenericParam) {
19    if let Some(idx) = first_default_or_const_param_position(generics) {
20        generics.params.insert(idx, type_param)
21    } else {
22        generics.params.push(type_param)
23    }
24}
25
26/// Converts `GenericParams` into `GenericArguments`.
27pub fn to_arguments(generics: &Generics) -> GenericArguments {
28    let mut args: GenericArguments = Punctuated::new();
29    args.extend(generics.params.iter().map(|param| match param {
30        GenericParam::Type(type_param) => new_generic_type_arg(type_param.ident.clone()),
31        GenericParam::Lifetime(lifetime_param) => {
32            GenericArgument::Lifetime(lifetime_param.lifetime.clone())
33        }
34        GenericParam::Const(const_param) => new_generic_type_arg(const_param.ident.clone()),
35    }));
36    args
37}
38
39// Creates a `GenericArgument` from an `Ident`
40fn new_generic_type_arg(ident: Ident) -> GenericArgument {
41    GenericArgument::Type(Type::Path(TypePath {
42        path: Path::from(ident),
43        qself: None,
44    }))
45}
yew_macro/derive_props/generics.rs

yew_macro/derive_props/
generics.rs
