Trait FromMeta
macro_input
pub trait FromMeta { pub fn from(meta: Option<Meta>) -> Result<Self, Error>; }
a trait for extracting a value from Option<syn::Meta>
Option<syn::Meta>
pub fn from(meta: Option<Meta>) -> Result<Self, Error>
extract the value
impl FromMeta for Option<()>
pub fn from(meta: Option<Meta>) -> Result<Option<()>, Error>
impl<F> FromMeta for F where F: FromLit,
pub fn from(meta: Option<Meta>) -> Result<F, Error>