rust宏 #11
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struct 派生宏 个人实现版本 参考use proc_macro::TokenStream;
use syn::{spanned::Spanned};
// use syn::{parse_quote};
use quote;
pub fn derive(input: TokenStream) -> TokenStream {
let st = syn::parse_macro_input!(input as syn::DeriveInput);
// TokenStream::new()
match do_expand(&st) {
Ok(token_stream) => token_stream.into(),
Err(e) => e.to_compile_error().into(),
}
}
type StructFields = syn::punctuated::Punctuated<syn::Field, syn::Token![,]>;
fn get_fields_from_derive_input(st: &syn::DeriveInput) -> syn::Result<&StructFields> {
if let syn::Data::Struct(
syn::DataStruct {
fields: syn::Fields::Named(
syn::FieldsNamed {
ref named,
..
}
),
..
}
) = st.data {
Ok(named)
} else {
Err(syn::Error::new_spanned(st, "Must Define On Struct, Not Allow On Enum Or Union".to_string()))
}
}
fn get_generic_inner_type<'a>(t: &'a syn::Type, out_ident_name: &str) -> Option<&'a syn::Type> {
if let syn::Type::Path(
syn::TypePath {
path: syn::Path {
segments,
..
},
..
}
) = t {
if let Some(seg) = segments.last() {
if seg.ident.to_string() == out_ident_name {
if let syn::PathArguments::AngleBracketed(
syn::AngleBracketedGenericArguments {
args,
..
}
) = &seg.arguments {
if let Some(syn::GenericArgument::Type(inner_type)) = args.first() {
return Some(inner_type);
}
}
}
}
}
None
}
enum AttrType {
Struct,
// Field,
}
fn get_attr(attrs: &Vec<syn::Attribute>, attr_name: &str, attr_type: AttrType) -> syn::Result<Option<syn::Ident>> {
// #[arel="users"]
// for attr in attrs {
// if let Ok(
// syn::Meta::NameValue(
// syn::MetaNameValue {
// ref path,
// ref lit,
// ..
// }
// )
// ) = attr.parse_meta() {
// if path.is_ident("arel") {
// if let syn::Lit::Str(ref ident_str) = lit {
// return Ok(Some(syn::Ident::new(ident_str.value().as_str(), attr.span())));
// }
// }
// }
// }
// #[arel(table_name="users")]
for attr in attrs {
if let Ok(
syn::Meta::List(
syn::MetaList {
ref path,
ref nested,
..
}
)
) = attr.parse_meta() {
for segment in path.segments.iter() {
if segment.ident == "arel" {
for nested_item in nested.iter() {
if let syn::NestedMeta::Meta(syn::Meta::NameValue(kv)) = nested_item {
if let syn::Lit::Str(ref ident_str) = kv.lit {
if kv.path.is_ident(attr_name) {
return Ok(Some(syn::Ident::new(ident_str.value().as_str(), attr.span())));
} else { // 校验
match attr_type {
AttrType::Struct => {
let support_attr_names = vec!["table_name"];
for attr_name in &support_attr_names {
if !kv.path.is_ident(attr_name) {
return Err(syn::Error::new_spanned(&kv.path, format!("Struct Only Support Attrs: {:?}", &support_attr_names)));
}
}
},
// AttrType::Field => {
// let support_attr_names = vec!["table_column_name"];
// for attr_name in &support_attr_names {
// if !kv.path.is_ident(attr_name) {
// return Err(syn::Error::new_spanned(&kv.path, format!("Field Only Support Attrs: {:?}", &support_attr_names)));
// }
// }
// }
}
}
}
}
}
}
}
}
}
Ok(None)
}
fn builde_struct_fields(st: &syn::DeriveInput) -> syn::Result<(proc_macro2::TokenStream, proc_macro2::TokenStream, proc_macro2::TokenStream, proc_macro2::TokenStream)> {
let fields = get_fields_from_derive_input(st)?;
let idents: Vec<_> = fields.iter().map(|f| &f.ident).collect();
let types: Vec<_> = fields.iter().map(|f| &f.ty).collect();
Ok(
(
// first
{
let types: Vec<_> = fields.iter().map(|f| {
// &f.ty
if let Some(ty_inner_type) = get_generic_inner_type(&f.ty, "Option") {
quote::quote! {
std::option::Option<#ty_inner_type>
}
} else if let Some(_) = get_generic_inner_type(&f.ty, "Vec") {
let origin_type = &f.ty;
quote::quote! {
#origin_type
}
} else {
let origin_type = &f.ty;
quote::quote! {
std::option::Option<#origin_type>
}
}
}).collect();
quote::quote! {
#(#idents: #types),*
}
},
// second
// quote::quote! {
// #(#idents: std::option::Option::None),*
// },
{
let mut final_token_stream = proc_macro2::TokenStream::new();
for (ident, r#type) in idents.iter().zip(types.iter()) {
let token_stream_piece;
if let Some(_) = get_generic_inner_type(r#type, "Vec") {
token_stream_piece = quote::quote! {
#ident: std::vec::Vec::new(),
};
} else {
token_stream_piece = quote::quote! {
#ident: std::option::Option::None,
};
}
final_token_stream.extend(token_stream_piece);
}
final_token_stream
},
// third
// quote::quote! {
// #(pub fn #idents(&mut self, #idents: #types) -> &mut Self {
// self.#idents = std::option::Option::Some(#idents);
// self
// })*
// },
{
let mut final_token_stream = proc_macro2::TokenStream::new();
for (ident, r#type) in idents.iter().zip(types.iter()) {
let token_stream_piece;
if let Some(_) = get_generic_inner_type(r#type, "Vec") {
token_stream_piece = quote::quote! {
fn #ident(&mut self, #ident: #r#type) -> &mut Self {
self.#ident = #ident;
self
}
};
} else {
// T -> T, Option<T> -> T
let r#type = if let Some(inner_type) = get_generic_inner_type(r#type, "Option") { inner_type } else { r#type };
token_stream_piece = quote::quote! {
fn #ident(&mut self, #ident: #r#type) -> &mut Self {
self.#ident = std::option::Option::Some(#ident);
self
}
};
}
final_token_stream.extend(token_stream_piece);
}
final_token_stream
},
// fourth
{
let segments: Vec<_> = fields.iter().filter(|f| {
get_generic_inner_type(&f.ty, "Option").is_none() && get_generic_inner_type(&f.ty, "Vec").is_none()
}).map(|f| {
let ident = &f.ident;
quote::quote! {
if self.#ident.is_none() {
return Err(anyhow::anyhow!("{} Not Allow None", stringify!(#ident)));
}
}
}).collect();
quote::quote! {
pub fn validate(&self) -> anyhow::Result<()> {
#(#segments)*
Ok(())
}
}
}
)
)
}
fn do_expand(st: &syn::DeriveInput) -> syn::Result<proc_macro2::TokenStream> {
let struct_ident = &st.ident;
let struct_name_literal = struct_ident.to_string();
let arel_struct_name_literal = format!("{}Arel", struct_name_literal);
let arel_struct_ident = &syn::Ident::new(&arel_struct_name_literal, st.span());
let (
builder_fields_def,
builder_fields_init_clauses,
builder_setter_functions,
validate_function,
) = builde_struct_fields(st)?;
// table_name_function
let table_name_function = {
if let Some(table_name_ident) = get_attr(&st.attrs, "table_name", AttrType::Struct)? {
quote::quote! {
fn table_name() -> String {
stringify!(#table_name_ident).to_string()
}
}
} else {
proc_macro2::TokenStream::new()
}
};
// trait限定 使用eg: impl #impl_generics #arel_struct_ident #type_generics #where_clause
// let mut generics = st.generics.clone();
// let (impl_generics, type_generics, where_clause) = {
// // for param in generics.params.iter_mut() {
// // if let syn::GenericParam::Type(t) = param {
// // // 对每个trait 额外增加Debug限定 eg: struct User<T: Clone> => struct User<T: Clone + Debug>
// // t.bounds.push(parse_quote!(std::fmt::Debug))
// // }
// // }
// generics.split_for_impl()
// };
let ret = quote::quote! {
// User
impl #struct_ident {
fn table() -> arel::table::Table<#arel_struct_ident> { #arel_struct_ident::table() }
fn query() -> arel::table::Table<#arel_struct_ident> { #arel_struct_ident::query() }
fn lock() -> arel::table::Table<#arel_struct_ident> { #arel_struct_ident::lock() }
fn create(condition: serde_json::Value) -> arel::table::Table<#arel_struct_ident> { #arel_struct_ident::create(condition) }
fn update_all(condition: serde_json::Value) -> arel::table::Table<#arel_struct_ident> { #arel_struct_ident::update_all(condition) }
fn delete_all(condition: serde_json::Value) -> arel::table::Table<#arel_struct_ident> { #arel_struct_ident::delete_all(condition) }
}
// UserArel
#[derive(::core::clone::Clone, ::core::fmt::Debug)]
pub struct #arel_struct_ident {
#builder_fields_def
}
impl arel::ArelAble for #arel_struct_ident {
#table_name_function
fn primary_key() -> &'static str { "id" }
}
impl #arel_struct_ident {
pub fn new() -> Self {
Self {
#builder_fields_init_clauses
}
}
#builder_setter_functions
#validate_function
}
};
Ok(ret)
} |
其他rust宏解析器 |
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属性式过程宏
参考资料： https://blog.ideawand.com/2021/02/27/rust_procedural_macro/rust_proc_marco_workshop_guide-01/
初始化项目
cargo new my_demo --bin cd my_demo cargo new proc_macro_first --libmy_demo/proc_macro_first/Cargo.toml, 添加：my_demo/proc_macro_first/src/lib.rs, 添加：my_demo/Cargo.toml, 添加：my_demo/src/main.rs, 添加：执行`cargo check`
* 使用
syn将TokenStream转换成更高级的TokenStream,quoto!可以将高级的TokenStream转换回函数支持的返回值类型的TokenStream进行返回my_demo/proc_macro_first/Cargo.toml, 添加：my_demo/proc_macro_first/src/lib.rs, 添加：执行`cargo check`
派生式过程宏
derive参考资料
* 第一关
my_demo/proc_macro_first/src/lib.rs, 写入：my_demo/src/main.rs, 写入：执行`cargo check`
* 其他关卡，完整代码
my_demo/proc_macro_first/Cargo.toml, 添加：my_demo/proc_macro_first/src/lib.rs, 更改为：# cargo install cargo-expand cargo expand生成结果打印如下：
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