Struct syn::Ident

pub struct Ident {
    pub span: Span,
    // some fields omitted
}

A word of Rust code, such as a keyword or 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.

extern crate syn;
use syn::Ident;

let ident = Ident::from("another_identifier");

When the ident is used in Macros 1.1 output, it needs to be turned into a token stream. This is easy to do using the quote! macro from the quote crate.

// Create tokens using the ident.
let expanded = quote! { let #ident = 10; };

// Derive a new ident from the existing one.
let temp_ident = Ident::from(format!("new_{}", ident));
let expanded = quote! { let $temp_ident = 10; };

If syn is used to parse existing Rust source code, it is often useful to convert the Ident to a more generic string data type at some point. The methods as_ref() and to_string() achieve this.

// 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

Methods

impl Ident

pub fn new(s: &str, span: Span) -> Self

Creates a new Ident from the structured items. This is mainly used by the parser to create Idents from existing Rust source code.

Creating new Idents programmatically is easier with Ident::from.

Trait Implementations

impl From<Ident> for Meta

fn from(e: Ident) -> Meta

Performs the conversion.

impl From<Ident> for TypeParam

fn from(ident: Ident) -> Self

Performs the conversion.

impl Synom for Ident

fn parse(input: Cursor) -> PResult<Self>

fn description() -> Option<&'static str>

impl ToTokens for Ident

fn to_tokens(&self, tokens: &mut Tokens)

Write self to the given Tokens.

fn into_tokens(self) -> Tokens

Convert self directly into a Tokens object.

impl Copy for Ident

impl Clone for Ident

fn clone(&self) -> Ident

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Ident

fn fmt(&self, __arg_0: &mut Formatter) -> Result

Formats the value using the given formatter.

impl<'a> From<&'a str> for Ident

fn from(s: &str) -> Self

Performs the conversion.

impl From<Self_> for Ident

fn from(tok: Self_) -> Self

Performs the conversion.

impl From<CapSelf> for Ident

fn from(tok: CapSelf) -> Self

Performs the conversion.

impl From<Super> for Ident

fn from(tok: Super) -> Self

Performs the conversion.

impl From<Crate> for Ident

fn from(tok: Crate) -> Self

Performs the conversion.

impl<'a> From<Cow<'a, str>> for Ident

fn from(s: Cow<'a, str>) -> Self

Performs the conversion.

impl From<String> for Ident

fn from(s: String) -> Self

Performs the conversion.

impl AsRef<str> for Ident

fn as_ref(&self) -> &str

Performs the conversion.

impl Display for Ident

fn fmt(&self, formatter: &mut Formatter) -> Result

Formats the value using the given formatter.

impl<T: ?Sized> PartialEq<T> for Ident where
    T: AsRef<str>, 

fn eq(&self, other: &T) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

impl Eq for Ident

impl PartialOrd for Ident

fn partial_cmp(&self, other: &Ident) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl Ord for Ident

fn cmp(&self, other: &Ident) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

impl Hash for Ident

fn hash<H: Hasher>(&self, h: &mut H)

Feeds this value into the given [Hasher].

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given [Hasher].