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#[cfg(test)]
mod tests {
use proc_macro2::Span;
use procmeta_core::{expr::FromMetaExpr, parser::MetaParser};
use syn::{
parse::ParseStream, parse_quote, Error, ItemStruct, LitInt, LitStr, Meta, MetaNameValue,
Token,
};
#[test]
fn test_parse() -> anyhow::Result<()> {
enum Context {
Note(LitStr),
NoteNameAge { name: LitStr, age: LitInt },
NoteName { name: LitStr },
}
impl MetaParser for Context {
fn parse(meta: &Meta) -> syn::Result<Self> {
let meta_path = meta.path();
if meta_path.is_ident("note") {
let result = meta.require_list();
if let Ok(list) = result {
let result =
list.parse_args_with(|stream: ParseStream| -> syn::Result<Context> {
let mut uname_1: Option<LitStr> = None;
let mut index = 0;
loop {
if stream.is_empty() {
break;
}
index += 1;
if index == 1i32 {
uname_1 = Some(stream.parse()?);
}
if stream.is_empty() {
break;
}
let _comma: Token ! [,] = stream.parse()?;
}
Ok(Context::Note(uname_1.ok_or_else(|| {
syn::Error::new(stream.span(), "Expected list")
})?))
});
if let Ok(result) = result {
return Ok(result);
}
}
let result = meta.require_list();
if let Ok(list) = result {
let result =
list.parse_args_with(|stream: ParseStream| -> syn::Result<Context> {
let mut name: Option<LitStr> = None;
let mut age: Option<LitInt> = None;
loop {
if stream.is_empty() {
break;
}
let nv: MetaNameValue = stream.parse()?;
if nv.path.is_ident("name") {
name = Some(LitStr::try_from_expr(nv.value.clone())?);
}
if nv.path.is_ident("age") {
age = Some(LitInt::try_from_expr(nv.value.clone())?);
}
if stream.is_empty() {
break;
}
let _comma: Token ! [,] = stream.parse()?;
}
Ok(Context::NoteNameAge {
name: name.ok_or_else(|| {
syn::Error::new(stream.span(), "missing`name`")
})?,
age: age.ok_or_else(|| {
syn::Error::new(stream.span(), "missing`age`")
})?,
})
});
if let Ok(result) = result {
return Ok(result);
}
}
let result = meta.require_list();
if let Ok(list) = result {
let result =
list.parse_args_with(|stream: ParseStream| -> syn::Result<Context> {
let mut name: Option<LitStr> = None;
loop {
if stream.is_empty() {
break;
}
let nv: MetaNameValue = stream.parse()?;
if nv.path.is_ident("name") {
name = Some(LitStr::try_from_expr(nv.value.clone())?);
}
if stream.is_empty() {
break;
}
let _comma: Token ! [,] = stream.parse()?;
}
Ok(Context::NoteName {
name: name.ok_or_else(|| {
syn::Error::new(stream.span(), "missing`name`")
})?,
})
});
if let Ok(result) = result {
return Ok(result);
}
};
}
Err(Error::new(Span::call_site(), "unrecognized writing method"))
}
}
let input: ItemStruct = parse_quote! {
#[derive(ApiModel)]
#[note("nihao")]
#[note(name = "zhangsan", age = 18)]
#[note(name = "lisi")]
pub struct MyStruct {
pub name: String,
}
};
let attrs = input.attrs;
for attr in attrs {
let context = Context::parse(&attr.meta);
if let Ok(context) = context {
match context {
Context::Note(lit) => {
println!("{}", lit.value());
}
Context::NoteNameAge { name, age } => {
println!(
"name = {}, age = {}",
name.value(),
age.base10_parse::<i64>().unwrap()
);
}
Context::NoteName { name } => {
println!("name = {}", name.value());
}
}
}
}
Ok(())
}
}