codama_attributes/codama_directives/
fixed_size_directive.rs

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
use codama_syn_helpers::{extensions::*, Meta};

#[derive(Debug, PartialEq)]
pub struct FixedSizeDirective {
    pub size: usize,
}

impl FixedSizeDirective {
    pub fn parse(meta: &Meta) -> syn::Result<Self> {
        let pv = meta.assert_directive("fixed_size")?.as_path_value()?;
        let size = pv.value.as_expr()?.as_literal_integer()?;
        Ok(Self { size })
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn ok() {
        let meta: Meta = syn::parse_quote! { fixed_size = 42 };
        let directive = FixedSizeDirective::parse(&meta).unwrap();
        assert_eq!(directive, FixedSizeDirective { size: 42 });
    }
}