Struct syn::Ident [−][src]
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.
- The empty string is not an identifier. Use
Option<Ident>
. - 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 Parse
implementation rejects
Rust keywords. Use input.call(Ident::parse_any)
when parsing to match the
behaviour of Ident::new
.
Examples
A new ident can be created from a string using the Ident::new
function.
A span must be provided explicitly which governs the name resolution
behavior of the resulting identifier.
use proc_macro2::{Ident, Span}; fn main() { let call_ident = Ident::new("calligraphy", Span::call_site()); println!("{}", call_ident); }
An ident can be interpolated into a token stream using the quote!
macro.
use proc_macro2::{Ident, Span}; use quote::quote; fn main() { let ident = Ident::new("demo", Span::call_site()); // 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::new(&format!("new_{}", ident), Span::call_site()); let expanded = quote! { let #temp_ident = 10; }; }
A string representation of the ident is available through the to_string()
method.
// Examine the ident as a string. let ident_string = ident.to_string(); if ident_string.len() > 60 { println!("Very long identifier: {}", ident_string) }
Implementations
impl Ident
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pub fn new(string: &str, span: Span) -> Ident
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Creates a new Ident
with the given string
as well as the specified
span
.
The string
argument must be a valid identifier permitted by the
language, otherwise the function will panic.
Note that span
, currently in rustc, configures the hygiene information
for this identifier.
As of this time Span::call_site()
explicitly opts-in to “call-site”
hygiene meaning that identifiers created with this span will be resolved
as if they were written directly at the location of the macro call, and
other code at the macro call site will be able to refer to them as well.
Later spans like Span::def_site()
will allow to opt-in to
“definition-site” hygiene meaning that identifiers created with this
span will be resolved at the location of the macro definition and other
code at the macro call site will not be able to refer to them.
Due to the current importance of hygiene this constructor, unlike other
tokens, requires a Span
to be specified at construction.
Panics
Panics if the input string is neither a keyword nor a legal variable
name. If you are not sure whether the string contains an identifier and
need to handle an error case, use
syn::parse_str
::<Ident>
rather than Ident::new
.
pub fn span(&self) -> Span
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Returns the span of this Ident
.
pub fn set_span(&mut self, span: Span)
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Configures the span of this Ident
, possibly changing its hygiene
context.
Trait Implementations
impl Clone for Ident
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impl Debug for Ident
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impl Display for Ident
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Prints the identifier as a string that should be losslessly convertible back into the same identifier.
impl Eq for Ident
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impl From<Crate> for Ident
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impl From<Extern> for Ident
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impl From<Ident> for TokenTree
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impl From<Ident> for TypeParam
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impl From<SelfType> for Ident
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impl From<SelfValue> for Ident
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impl From<Super> for Ident
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impl From<Underscore> for Ident
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fn from(token: Underscore) -> Ident
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impl Hash for Ident
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pub fn hash<H>(&self, hasher: &mut H) where
H: Hasher,
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H: Hasher,
pub fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher,
1.3.0[src]
H: Hasher,
impl IdentExt for Ident
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fn parse_any(input: ParseStream<'_>) -> Result<Self>
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fn unraw(&self) -> Ident
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const peek_any: PeekFn
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impl IdentFragment for Ident
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pub fn span(&self) -> Option<Span>
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pub fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
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impl Ord for Ident
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pub fn cmp(&self, other: &Ident) -> Ordering
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#[must_use]pub fn max(self, other: Self) -> Self
1.21.0[src]
#[must_use]pub fn min(self, other: Self) -> Self
1.21.0[src]
#[must_use]pub fn clamp(self, min: Self, max: Self) -> Self
1.50.0[src]
impl Parse for Ident
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fn parse(input: ParseStream<'_>) -> Result<Self>
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impl PartialEq<Ident> for Ident
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pub fn eq(&self, other: &Ident) -> bool
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#[must_use]pub fn ne(&self, other: &Rhs) -> bool
1.0.0[src]
impl<T> PartialEq<T> for Ident where
T: AsRef<str> + ?Sized,
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T: AsRef<str> + ?Sized,
impl PartialOrd<Ident> for Ident
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pub fn partial_cmp(&self, other: &Ident) -> Option<Ordering>
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#[must_use]pub fn lt(&self, other: &Rhs) -> bool
1.0.0[src]
#[must_use]pub fn le(&self, other: &Rhs) -> bool
1.0.0[src]
#[must_use]pub fn gt(&self, other: &Rhs) -> bool
1.0.0[src]
#[must_use]pub fn ge(&self, other: &Rhs) -> bool
1.0.0[src]
impl ToTokens for Ident
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pub fn to_tokens(&self, tokens: &mut TokenStream)
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pub fn to_token_stream(&self) -> TokenStream
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pub fn into_token_stream(self) -> TokenStream
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impl Token for Ident
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Auto Trait Implementations
impl RefUnwindSafe for Ident
impl !Send for Ident
impl !Sync for Ident
impl Unpin for Ident
impl UnwindSafe for Ident
Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
pub fn borrow_mut(&mut self) -> &mut T
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impl<T> From<T> for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> Spanned for T where
T: Spanned + ?Sized,
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T: Spanned + ?Sized,
impl<T> ToOwned for T where
T: Clone,
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T: Clone,
type Owned = T
The resulting type after obtaining ownership.
pub fn to_owned(&self) -> T
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pub fn clone_into(&self, target: &mut T)
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impl<T> ToString for T where
T: Display + ?Sized,
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T: Display + ?Sized,
impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,