Struct Literal

pub struct Literal(/* private fields */);

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 Idents.

Implementations

impl Literal

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 might not survive round-trips 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.

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 might not survive round-trips 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.

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 might not survive round-trips 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.

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 might not survive round-trips 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.

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 might not survive round-trips 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.

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 might not survive round-trips 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.

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 might not survive round-trips 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.

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 might not survive round-trips 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.

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 might not survive round-trips 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.

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 might not survive round-trips 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.

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 might not survive round-trips 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.

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 might not survive round-trips 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.

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 might not survive rountrips 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.

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 might not survive rountrips 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.

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 might not survive rountrips 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.

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 might not survive rountrips 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.

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 might not survive rountrips 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.

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 might not survive rountrips 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.

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 might not survive rountrips 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.

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 might not survive rountrips 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.

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 might not survive rountrips 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.

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 might not survive rountrips 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.

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 might not survive rountrips 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.

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 might not survive rountrips 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.

pub fn f32_unsuffixed(n: 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 might not survive rountrips 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.

pub fn f32_suffixed(n: 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 might not survive rountrips 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.

pub fn f64_unsuffixed(n: 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 might not survive rountrips 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.

pub fn f64_suffixed(n: 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 might not survive rountrips 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.

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

String literal.

pub fn character(ch: char) -> Literal

Character literal.

pub fn byte_character(byte: u8) -> Literal

Byte character literal.

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

Byte string literal.

pub fn c_string(string: &CStr) -> Literal

C string literal.

pub fn span(&self) -> Span

Returns the span encompassing this literal.

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

Configures the span associated for this literal.

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

🔬This is a nightly-only experimental API. (proc_macro_span #54725)

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.

Trait Implementations

impl Clone for Literal

fn clone(&self) -> Literal

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Literal

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

Formats the value using the given formatter.

impl Display for Literal

Prints the literal as a string that should be losslessly convertible back into the same literal (except for possible rounding for floating point literals).

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

Formats the value using the given formatter.

impl From<Literal> for TokenTree

fn from(g: Literal) -> TokenTree

Converts to this type from the input type.

impl FromStr for Literal

Parse a single literal from its stringified representation.

In order to parse successfully, the input string must not contain anything but the literal token. Specifically, it must not contain whitespace or comments in addition to the literal.

The resulting literal token will have a Span::call_site() span.

NOTE: some errors may cause panics instead of returning LexError. We reserve the right to change these errors into LexErrors later.

type Err = LexError

The associated error which can be returned from parsing.

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

Parses a string s to return a value of this type.