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use crate::expr::Expr;
use proc_macro2::TokenStream;
use syn::parse::{Parse, ParseStream, Result};
use syn::Token;
pub struct Args {
pub condition: Expr,
pub then: Then,
}
pub enum Then {
Const(Token![const]),
Attribute(TokenStream),
}
impl Parse for Args {
fn parse(input: ParseStream) -> Result<Self> {
let condition: Expr = input.parse()?;
input.parse::<Token![,]>()?;
if input.is_empty() {
return Err(input.error("expected one or more attrs"));
}
let const_token: Option<Token![const]> = input.parse()?;
let then = if let Some(const_token) = const_token {
input.parse::<Option<Token![,]>>()?;
Then::Const(const_token)
} else {
input.parse().map(Then::Attribute)?
};
Ok(Args { condition, then })
}
}
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