/
refident.rs
67 lines (58 loc) · 1.48 KB
/
refident.rs
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/// Provide `RefIdent` and `MaybeIdent` traits that give a shortcut to extract identity reference
/// (`syn::Ident` struct).
use proc_macro2::Ident;
use syn::{FnArg, Pat, PatType, Type};
pub trait RefIdent {
/// Return the reference to ident if any
fn ident(&self) -> &Ident;
}
pub trait MaybeIdent {
/// Return the reference to ident if any
fn maybe_ident(&self) -> Option<&Ident>;
}
impl<I: RefIdent> MaybeIdent for I {
fn maybe_ident(&self) -> Option<&Ident> {
Some(self.ident())
}
}
impl RefIdent for Ident {
fn ident(&self) -> &Ident {
self
}
}
impl<'a> RefIdent for &'a Ident {
fn ident(&self) -> &Ident {
*self
}
}
impl MaybeIdent for FnArg {
fn maybe_ident(&self) -> Option<&Ident> {
match self {
FnArg::Typed(PatType { pat, .. }) => match pat.as_ref() {
Pat::Ident(ident) => Some(&ident.ident),
_ => None,
},
_ => None,
}
}
}
impl MaybeIdent for Type {
fn maybe_ident(&self) -> Option<&Ident> {
match self {
Type::Path(tp) if tp.qself.is_none() => tp.path.get_ident(),
_ => None,
}
}
}
pub trait MaybeType {
/// Return the reference to type if any
fn maybe_type(&self) -> Option<&Type>;
}
impl MaybeType for FnArg {
fn maybe_type(&self) -> Option<&Type> {
match self {
FnArg::Typed(PatType { ty, .. }) => Some(ty.as_ref()),
_ => None,
}
}
}