codama_attributes/codama_directives/
size_prefix_directive.rs

1use crate::utils::FromMeta;
2use codama_nodes::{NestedTypeNode, NumberTypeNode, TypeNode};
3use codama_syn_helpers::{extensions::*, Meta};
4
5#[derive(Debug, PartialEq)]
6pub struct SizePrefixDirective {
7    pub prefix: NestedTypeNode<NumberTypeNode>,
8}
9
10impl SizePrefixDirective {
11    pub fn parse(meta: &Meta) -> syn::Result<Self> {
12        let pv = meta.assert_directive("size_prefix")?.as_path_value()?;
13        let node = TypeNode::from_meta(&pv.value)?;
14        let prefix = match NestedTypeNode::<NumberTypeNode>::try_from(node) {
15            Ok(node) => node,
16            Err(_) => return Err(pv.value.error("prefix must be a NumberTypeNode")),
17        };
18        Ok(Self { prefix })
19    }
20}
21
22#[cfg(test)]
23mod tests {
24    use super::*;
25    use codama_nodes::NumberFormat::U32;
26
27    #[test]
28    fn ok() {
29        let meta: Meta = syn::parse_quote! { size_prefix = number(u32) };
30        let directive = SizePrefixDirective::parse(&meta).unwrap();
31        assert_eq!(
32            directive,
33            SizePrefixDirective {
34                prefix: NumberTypeNode::le(U32).into(),
35            }
36        );
37    }
38}