# Struct proc_macro2::Literal

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    pub struct Literal { /* private fields */ }

Expand description

A literal string (`"hello"`), byte string (`b"hello"`), character (`'a'`), byte character (`b'a'`), an integer or floating point number with or without a suffix (`1`, `1u8`, `2.3`, `2.3f32`).

Boolean literals like `true` and `false` do not belong here, they are `Ident`s.

## Implementations

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### impl Literal

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#### pub fn u8_suffixed(n: u8) -> Literal

Creates a new suffixed integer literal with the specified value.

This function will create an integer like `1u32` where the integer value specified is the first part of the token and the integral is also suffixed at the end. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn u16_suffixed(n: u16) -> Literal

Creates a new suffixed integer literal with the specified value.

This function will create an integer like `1u32` where the integer value specified is the first part of the token and the integral is also suffixed at the end. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn u32_suffixed(n: u32) -> Literal

Creates a new suffixed integer literal with the specified value.

This function will create an integer like `1u32` where the integer value specified is the first part of the token and the integral is also suffixed at the end. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn u64_suffixed(n: u64) -> Literal

Creates a new suffixed integer literal with the specified value.

This function will create an integer like `1u32` where the integer value specified is the first part of the token and the integral is also suffixed at the end. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn u128_suffixed(n: u128) -> Literal

Creates a new suffixed integer literal with the specified value.

This function will create an integer like `1u32` where the integer value specified is the first part of the token and the integral is also suffixed at the end. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn usize_suffixed(n: usize) -> Literal

Creates a new suffixed integer literal with the specified value.

This function will create an integer like `1u32` where the integer value specified is the first part of the token and the integral is also suffixed at the end. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn i8_suffixed(n: i8) -> Literal

Creates a new suffixed integer literal with the specified value.

This function will create an integer like `1u32` where the integer value specified is the first part of the token and the integral is also suffixed at the end. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn i16_suffixed(n: i16) -> Literal

Creates a new suffixed integer literal with the specified value.

This function will create an integer like `1u32` where the integer value specified is the first part of the token and the integral is also suffixed at the end. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn i32_suffixed(n: i32) -> Literal

Creates a new suffixed integer literal with the specified value.

This function will create an integer like `1u32` where the integer value specified is the first part of the token and the integral is also suffixed at the end. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn i64_suffixed(n: i64) -> Literal

Creates a new suffixed integer literal with the specified value.

This function will create an integer like `1u32` where the integer value specified is the first part of the token and the integral is also suffixed at the end. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn i128_suffixed(n: i128) -> Literal

Creates a new suffixed integer literal with the specified value.

This function will create an integer like `1u32` where the integer value specified is the first part of the token and the integral is also suffixed at the end. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn isize_suffixed(n: isize) -> Literal

Creates a new suffixed integer literal with the specified value.

This function will create an integer like `1u32` where the integer value specified is the first part of the token and the integral is also suffixed at the end. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn u8_unsuffixed(n: u8) -> Literal

Creates a new unsuffixed integer literal with the specified value.

This function will create an integer like `1` where the integer value specified is the first part of the token. No suffix is specified on this token, meaning that invocations like `Literal::i8_unsuffixed(1)` are equivalent to `Literal::u32_unsuffixed(1)`. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn u16_unsuffixed(n: u16) -> Literal

Creates a new unsuffixed integer literal with the specified value.

This function will create an integer like `1` where the integer value specified is the first part of the token. No suffix is specified on this token, meaning that invocations like `Literal::i8_unsuffixed(1)` are equivalent to `Literal::u32_unsuffixed(1)`. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn u32_unsuffixed(n: u32) -> Literal

Creates a new unsuffixed integer literal with the specified value.

This function will create an integer like `1` where the integer value specified is the first part of the token. No suffix is specified on this token, meaning that invocations like `Literal::i8_unsuffixed(1)` are equivalent to `Literal::u32_unsuffixed(1)`. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn u64_unsuffixed(n: u64) -> Literal

Creates a new unsuffixed integer literal with the specified value.

This function will create an integer like `1` where the integer value specified is the first part of the token. No suffix is specified on this token, meaning that invocations like `Literal::i8_unsuffixed(1)` are equivalent to `Literal::u32_unsuffixed(1)`. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn u128_unsuffixed(n: u128) -> Literal

Creates a new unsuffixed integer literal with the specified value.

This function will create an integer like `1` where the integer value specified is the first part of the token. No suffix is specified on this token, meaning that invocations like `Literal::i8_unsuffixed(1)` are equivalent to `Literal::u32_unsuffixed(1)`. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn usize_unsuffixed(n: usize) -> Literal

Creates a new unsuffixed integer literal with the specified value.

This function will create an integer like `1` where the integer value specified is the first part of the token. No suffix is specified on this token, meaning that invocations like `Literal::i8_unsuffixed(1)` are equivalent to `Literal::u32_unsuffixed(1)`. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn i8_unsuffixed(n: i8) -> Literal

Creates a new unsuffixed integer literal with the specified value.

This function will create an integer like `1` where the integer value specified is the first part of the token. No suffix is specified on this token, meaning that invocations like `Literal::i8_unsuffixed(1)` are equivalent to `Literal::u32_unsuffixed(1)`. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn i16_unsuffixed(n: i16) -> Literal

Creates a new unsuffixed integer literal with the specified value.

This function will create an integer like `1` where the integer value specified is the first part of the token. No suffix is specified on this token, meaning that invocations like `Literal::i8_unsuffixed(1)` are equivalent to `Literal::u32_unsuffixed(1)`. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn i32_unsuffixed(n: i32) -> Literal

Creates a new unsuffixed integer literal with the specified value.

This function will create an integer like `1` where the integer value specified is the first part of the token. No suffix is specified on this token, meaning that invocations like `Literal::i8_unsuffixed(1)` are equivalent to `Literal::u32_unsuffixed(1)`. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn i64_unsuffixed(n: i64) -> Literal

Creates a new unsuffixed integer literal with the specified value.

This function will create an integer like `1` where the integer value specified is the first part of the token. No suffix is specified on this token, meaning that invocations like `Literal::i8_unsuffixed(1)` are equivalent to `Literal::u32_unsuffixed(1)`. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn i128_unsuffixed(n: i128) -> Literal

Creates a new unsuffixed integer literal with the specified value.

This function will create an integer like `1` where the integer value specified is the first part of the token. No suffix is specified on this token, meaning that invocations like `Literal::i8_unsuffixed(1)` are equivalent to `Literal::u32_unsuffixed(1)`. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn isize_unsuffixed(n: isize) -> Literal

Creates a new unsuffixed integer literal with the specified value.

This function will create an integer like `1` where the integer value specified is the first part of the token. No suffix is specified on this token, meaning that invocations like `Literal::i8_unsuffixed(1)` are equivalent to `Literal::u32_unsuffixed(1)`. Literals created from negative numbers may not survive roundtrips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

Literals created through this method have the `Span::call_site()` span by default, which can be configured with the `set_span` method below.

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#### pub fn f64_unsuffixed(f: f64) -> Literal

Creates a new unsuffixed floating-point literal.

This constructor is similar to those like `Literal::i8_unsuffixed` where the float’s value is emitted directly into the token but no suffix is used, so it may be inferred to be a `f64` later in the compiler. Literals created from negative numbers may not survive round-trips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

##### Panics

This function requires that the specified float is finite, for example if it is infinity or NaN this function will panic.

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#### pub fn f64_suffixed(f: f64) -> Literal

Creates a new suffixed floating-point literal.

This constructor will create a literal like `1.0f64` where the value specified is the preceding part of the token and `f64` is the suffix of the token. This token will always be inferred to be an `f64` in the compiler. Literals created from negative numbers may not survive round-trips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

##### Panics

This function requires that the specified float is finite, for example if it is infinity or NaN this function will panic.

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#### pub fn f32_unsuffixed(f: f32) -> Literal

Creates a new unsuffixed floating-point literal.

This constructor is similar to those like `Literal::i8_unsuffixed` where the float’s value is emitted directly into the token but no suffix is used, so it may be inferred to be a `f64` later in the compiler. Literals created from negative numbers may not survive round-trips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

##### Panics

This function requires that the specified float is finite, for example if it is infinity or NaN this function will panic.

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#### pub fn f32_suffixed(f: f32) -> Literal

Creates a new suffixed floating-point literal.

This constructor will create a literal like `1.0f32` where the value specified is the preceding part of the token and `f32` is the suffix of the token. This token will always be inferred to be an `f32` in the compiler. Literals created from negative numbers may not survive round-trips through `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).

##### Panics

This function requires that the specified float is finite, for example if it is infinity or NaN this function will panic.

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#### pub fn string(string: &str) -> Literal

String literal.

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#### pub fn character(ch: char) -> Literal

Character literal.

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#### pub fn byte_string(s: &[u8]) -> Literal

Byte string literal.

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#### pub fn span(&self) -> Span

Returns the span encompassing this literal.

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#### pub fn set_span(&mut self, span: Span)

Configures the span associated for this literal.

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#### pub fn subspan<R: RangeBounds<usize>>(&self, range: R) -> Option<Span>

Returns a `Span` that is a subset of `self.span()` containing only the source bytes in range `range`. Returns `None` if the would-be trimmed span is outside the bounds of `self`.

Warning: the underlying `proc_macro::Literal::subspan` method is nightly-only. When called from within a procedural macro not using a nightly compiler, this method will always return `None`.

## Trait Implementations

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### impl Clone for Literal

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#### fn clone(&self) -> Literal

Returns a copy of the value. Read more

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

Performs copy-assignment from `source`. Read more

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### impl Debug for Literal

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#### fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more

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### impl Display for Literal

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#### fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more

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### impl From<Literal> for TokenTree

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#### fn from(g: Literal) -> TokenTree

Converts to this type from the input type.

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### impl FromStr for Literal

#### type Err = LexError

The associated error which can be returned from parsing.

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#### fn from_str(repr: &str) -> Result<Self, LexError>

Parses a string `s` to return a value of this type. Read more

## Auto Trait Implementations

### impl RefUnwindSafe for Literal

### impl !Send for Literal

### impl !Sync for Literal

### impl Unpin for Literal

### impl UnwindSafe for Literal

## Blanket Implementations

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### impl<T> Any for T where
T: 'static + ?Sized,

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#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more

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### impl<T> Borrow<T> for T where
T: ?Sized,

const: unstable · source

#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more

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### impl<T> BorrowMut<T> for T where
T: ?Sized,

const: unstable · source

#### fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more

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### impl<T> From<T> for T

const: unstable · source

#### fn from(t: T) -> T

Returns the argument unchanged.

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### impl<T, U> Into<U> for T where
U: From<T>,

const: unstable · source

#### fn into(self) -> U

Calls `U::from(self)`.

That is, this conversion is whatever the implementation of `From<T> for U` chooses to do.

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### impl<T> ToOwned for T where
T: Clone,

#### type Owned = T

The resulting type after obtaining ownership.

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#### fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more

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#### fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more

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### impl<T> ToString for T where
T: Display + ?Sized,

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#### default fn to_string(&self) -> String

Converts the given value to a `String`. Read more

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### impl<T, U> TryFrom<U> for T where
U: Into<T>,

#### type Error = Infallible

The type returned in the event of a conversion error.

const: unstable · source

#### fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.

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### impl<T, U> TryInto<U> for T where
U: TryFrom<T>,

#### type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.

const: unstable · source

#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.