Method _optional_str

crates/derive-impl/src/util.rs:165–188

(&self, key: &str)

    }

    pub fn _optional_str(&self, key: &str) -> Result<Option<String>> {
        let value = if let Some((_, meta)) = self.meta_map.get(key) {
            let Meta::NameValue(syn::MetaNameValue {
                value:
                    syn::Expr::Lit(syn::ExprLit {
                        lit: syn::Lit::Str(lit),
                        ..
                    }),
                ..
            }) = meta
            else {
                bail_span!(
                    meta,
                    "#[{}({} = ...)] must exist as a string",
                    self.meta_name(),
                    key
                )
            };
            Some(lit.value())
        } else {
            None
        };
        Ok(value)
    }

    pub fn _optional_path(&self, key: &str) -> Result<Option<syn::Path>> {
        let value = if let Some((_, meta)) = self.meta_map.get(key) {