Module syn::token[][src]

Tokens representing Rust punctuation, keywords, and delimiters.

The type names in this module can be difficult to keep straight, so we prefer to use the Token! macro instead. This is a type-macro that expands to the token type of the given token.

Example

The ItemStatic syntax tree node is defined like this.

pub struct ItemStatic {
    pub attrs: Vec<Attribute>,
    pub vis: Visibility,
    pub static_token: Token![static],
    pub mutability: Option<Token![mut]>,
    pub ident: Ident,
    pub colon_token: Token![:],
    pub ty: Box<Type>,
    pub eq_token: Token![=],
    pub expr: Box<Expr>,
    pub semi_token: Token![;],
}

Parsing

Keywords and punctuation can be parsed through the ParseStream::parse method. Delimiter tokens are parsed using the parenthesized!, bracketed! and braced! macros.

use syn::{Attribute, Result};
use syn::parse::{Parse, ParseStream};

// Parse the ItemStatic struct shown above.
impl Parse for ItemStatic {
    fn parse(input: ParseStream) -> Result<Self> {
        Ok(ItemStatic {
            attrs: input.call(Attribute::parse_outer)?,
            vis: input.parse()?,
            static_token: input.parse()?,
            mutability: input.parse()?,
            ident: input.parse()?,
            colon_token: input.parse()?,
            ty: input.parse()?,
            eq_token: input.parse()?,
            expr: input.parse()?,
            semi_token: input.parse()?,
        })
    }
}

Other operations

Every keyword and punctuation token supports the following operations.

Structs

Abstract

abstract

Add

+

AddEq

+=

And

&

AndAnd

&&

AndEq

&=

As

as

Async

async

At

@

Auto

auto

Await

await

Bang

!

Become

become

Box

box

Brace

{...}

Bracket

[...]

Break

break

Caret

^

CaretEq

^=

Colon

:

Colon2

::

Comma

,

Const

const

Continue

continue

Crate

crate

Default

default

Div

/

DivEq

/=

Do

do

Dollar

$

Dot

.

Dot2

..

Dot3

...

DotDotEq

..=

Dyn

dyn

Else

else

Enum

enum

Eq

=

EqEq

==

Extern

extern

FatArrow

=>

Final

final

Fn

fn

For

for

Ge

>=

Group

None-delimited group

Gt

>

If

if

Impl

impl

In

in

LArrow

<-

Le

<=

Let

let

Loop

loop

Lt

<

Macro

macro

Match

match

Mod

mod

Move

move

MulEq

*=

Mut

mut

Ne

!=

Or

|

OrEq

|=

OrOr

||

Override

override

Paren

(...)

Pound

#

Priv

priv

Pub

pub

Question

?

RArrow

->

Ref

ref

Rem

%

RemEq

%=

Return

return

SelfType

Self

SelfValue

self

Semi

;

Shl

<<

ShlEq

<<=

Shr

>>

ShrEq

>>=

Star

*

Static

static

Struct

struct

Sub

-

SubEq

-=

Super

super

Tilde

~

Trait

trait

Try

try

Type

type

Typeof

typeof

Underscore

_

Union

union

Unsafe

unsafe

Unsized

unsized

Use

use

Virtual

virtual

Where

where

While

while

Yield

yield

Traits

Token

Marker trait for types that represent single tokens.