1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
|
use crate::error::{Error, Result};
use crate::expr::{self, Expr};
use crate::{iter, token};
use proc_macro::{Span, TokenStream};
pub struct Args {
pub condition: Expr,
pub then: Then,
}
pub enum Then {
Const(Span),
Attribute(TokenStream),
}
pub fn parse(input: TokenStream) -> Result<Args> {
let ref mut input = iter::new(input);
let condition = expr::parse(input)?;
token::parse_punct(input, ',')?;
if input.peek().is_none() {
return Err(Error::new(Span::call_site(), "expected one or more attrs"));
}
let const_span = token::parse_optional_keyword(input, "const");
let then = if let Some(const_span) = const_span {
token::parse_optional_punct(input, ',');
token::parse_end(input)?;
Then::Const(const_span)
} else {
Then::Attribute(input.collect())
};
Ok(Args { condition, then })
}
|
