pub struct Ident {
pub span: Span,
/* private fields */
}
Expand description
A word of Rust code, which may be a keyword or legal variable name.
An identifier consists of at least one Unicode code point, the first of which has the XID_Start property and the rest of which have the XID_Continue property. An underscore may be used as the first character as long as it is not the only character.
- The empty string is not an identifier. Use
Option<Ident>
. - An underscore by itself is not an identifier. Use
Token![_]
instead. - A lifetime is not an identifier. Use
syn::Lifetime
instead.
An identifier constructed with Ident::new
is permitted to be a Rust
keyword, though parsing one through its Synom
implementation rejects
Rust keywords.
§Examples
A new ident can be created from a string using the Ident::from
function.
Idents produced by Ident::from
are set to resolve at the procedural macro
def site by default. A different span can be provided explicitly by using
Ident::new
.
extern crate syn;
extern crate proc_macro2;
use syn::Ident;
use proc_macro2::Span;
fn main() {
let def_ident = Ident::from("definitely");
let call_ident = Ident::new("calligraphy", Span::call_site());
println!("{} {}", def_ident, call_ident);
}
An ident can be interpolated into a token stream using the quote!
macro.
#[macro_use]
extern crate quote;
extern crate syn;
use syn::Ident;
fn main() {
let ident = Ident::from("demo");
// Create a variable binding whose name is this ident.
let expanded = quote! { let #ident = 10; };
// Create a variable binding with a slightly different name.
let temp_ident = Ident::from(format!("new_{}", ident));
let expanded = quote! { let #temp_ident = 10; };
}
A string representation of the ident is available through the as_ref()
and
to_string()
methods.
// Examine the ident as a &str.
let ident_str = ident.as_ref();
if ident_str.len() > 60 {
println!("Very long identifier: {}", ident_str)
}
// Create a String from the ident.
let ident_string = ident.to_string();
give_away(ident_string);
fn give_away(s: String) { /* ... */ }
Fields§
§span: Span
Implementations§
Trait Implementations§
Source§impl Ord for Ident
impl Ord for Ident
Source§impl PartialOrd for Ident
impl PartialOrd for Ident
impl Copy for Ident
impl Eq for Ident
Auto Trait Implementations§
impl Freeze for Ident
impl RefUnwindSafe for Ident
impl !Send for Ident
impl !Sync for Ident
impl Unpin for Ident
impl UnwindSafe for Ident
Blanket Implementations§
Source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
Source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Source§impl<T> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
T: Clone,
Source§impl<T> Spanned for Twhere
T: ToTokens,
impl<T> Spanned for Twhere
T: ToTokens,
Source§fn span(&self) -> Span
fn span(&self) -> Span
Span
covering the complete contents of this syntax tree
node, or Span::call_site()
if this node is empty.