// SPDX-License-Identifier: Apache-2.0 OR MIT /// Define a type that supports parsing and printing a multi-character symbol/// as if it were a punctuation token.////// # Usage////// ```/// syn::custom_punctuation!(LeftRightArrow, <=>);/// ```////// The generated syntax tree node supports the following operations just like/// any built-in punctuation token.////// - [Peeking] — `input.peek(LeftRightArrow)`////// - [Parsing] — `input.parse::<LeftRightArrow>()?`////// - [Printing] — `quote!( ... #lrarrow ... )`////// - Construction from a [`Span`] — `let lrarrow = LeftRightArrow(sp)`////// - Construction from multiple [`Span`] — `let lrarrow = LeftRightArrow([sp, sp, sp])`////// - Field access to its spans — `let spans = lrarrow.spans`////// [Peeking]: crate::parse::ParseBuffer::peek/// [Parsing]: crate::parse::ParseBuffer::parse/// [Printing]: quote::ToTokens/// [`Span`]: proc_macro2::Span////// # Example////// ```/// use proc_macro2::{TokenStream, TokenTree};/// use syn::parse::{Parse, ParseStream, Peek, Result};/// use syn::punctuated::Punctuated;/// use syn::Expr;////// syn::custom_punctuation!(PathSeparator, </>);////// // expr </> expr </> expr .../// struct PathSegments {/// segments: Punctuated<Expr, PathSeparator>,/// }////// impl Parse for PathSegments {/// fn parse(input: ParseStream) -> Result<Self> {/// let mut segments = Punctuated::new();////// let first = parse_until(input, PathSeparator)?;/// segments.push_value(syn::parse2(first)?);////// while input.peek(PathSeparator) {/// segments.push_punct(input.parse()?);////// let next = parse_until(input, PathSeparator)?;/// segments.push_value(syn::parse2(next)?);/// }////// Ok(PathSegments { segments })/// }/// }////// fn parse_until<E: Peek>(input: ParseStream, end: E) -> Result<TokenStream> {/// let mut tokens = TokenStream::new();/// while !input.is_empty() && !input.peek(end) {/// let next: TokenTree = input.parse()?;/// tokens.extend(Some(next));/// }/// Ok(tokens)/// }////// fn main() {/// let input = r#" a::b </> c::d::e "#;/// let _: PathSegments = syn::parse_str(input).unwrap();/// }/// ```#[macro_export]macro_rules! custom_punctuation { ($ident:ident, $($tt:tt)+) => { pub struct $ident { #[allow(dead_code)] pub spans: $crate::custom_punctuation_repr!($($tt)+), } #[doc(hidden)] #[allow(dead_code, non_snake_case)] pub fn $ident<__S: $crate::__private::IntoSpans<$crate::custom_punctuation_repr!($($tt)+)>>( spans: __S, ) -> $ident { let _validate_len = 0 $(+ $crate::custom_punctuation_len!(strict, $tt))*; $ident { spans: $crate::__private::IntoSpans::into_spans(spans) } } const _: () = { impl $crate::__private::Default for $ident { fn default() -> Self { $ident($crate::__private::Span::call_site()) } } $crate::impl_parse_for_custom_punctuation!($ident, $($tt)+); $crate::impl_to_tokens_for_custom_punctuation!($ident, $($tt)+); $crate::impl_clone_for_custom_punctuation!($ident, $($tt)+); $crate::impl_extra_traits_for_custom_punctuation!($ident, $($tt)+); }; };} // Not public API.#[cfg(feature = "parsing")]#[doc(hidden)]#[macro_export]macro_rules! impl_parse_for_custom_punctuation { ($ident:ident, $($tt:tt)+) => { impl $crate::__private::CustomToken for $ident { fn peek(cursor: $crate::buffer::Cursor) -> $crate::__private::bool { $crate::__private::peek_punct(cursor, $crate::stringify_punct!($($tt)+)) } fn display() -> &'static $crate::__private::str { $crate::__private::concat!("`", $crate::stringify_punct!($($tt)+), "`") } } impl $crate::parse::Parse for $ident { fn parse(input: $crate::parse::ParseStream) -> $crate::parse::Result<$ident> { let spans: $crate::custom_punctuation_repr!($($tt)+) = $crate::__private::parse_punct(input, $crate::stringify_punct!($($tt)+))?; Ok($ident(spans)) } } };} // Not public API.#[cfg(not(feature = "parsing"))]#[doc(hidden)]#[macro_export]macro_rules! impl_parse_for_custom_punctuation { ($ident:ident, $($tt:tt)+) => {};} // Not public API.#[cfg(feature = "printing")]#[doc(hidden)]#[macro_export]macro_rules! impl_to_tokens_for_custom_punctuation { ($ident:ident, $($tt:tt)+) => { impl $crate::__private::ToTokens for $ident { fn to_tokens(&self, tokens: &mut $crate::__private::TokenStream2) { $crate::__private::print_punct($crate::stringify_punct!($($tt)+), &self.spans, tokens) } } };} // Not public API.#[cfg(not(feature = "printing"))]#[doc(hidden)]#[macro_export]macro_rules! impl_to_tokens_for_custom_punctuation { ($ident:ident, $($tt:tt)+) => {};} // Not public API.#[cfg(feature = "clone-impls")]#[doc(hidden)]#[macro_export]macro_rules! impl_clone_for_custom_punctuation { ($ident:ident, $($tt:tt)+) => { impl $crate::__private::Copy for $ident {} #[allow(clippy::expl_impl_clone_on_copy)] impl $crate::__private::Clone for $ident { fn clone(&self) -> Self { *self } } };} // Not public API.#[cfg(not(feature = "clone-impls"))]#[doc(hidden)]#[macro_export]macro_rules! impl_clone_for_custom_punctuation { ($ident:ident, $($tt:tt)+) => {};} // Not public API.#[cfg(feature = "extra-traits")]#[doc(hidden)]#[macro_export]macro_rules! impl_extra_traits_for_custom_punctuation { ($ident:ident, $($tt:tt)+) => { impl $crate::__private::Debug for $ident { fn fmt(&self, f: &mut $crate::__private::Formatter) -> $crate::__private::FmtResult { $crate::__private::Formatter::write_str(f, $crate::__private::stringify!($ident)) } } impl $crate::__private::Eq for $ident {} impl $crate::__private::PartialEq for $ident { fn eq(&self, _other: &Self) -> $crate::__private::bool { true } } impl $crate::__private::Hash for $ident { fn hash<__H: $crate::__private::Hasher>(&self, _state: &mut __H) {} } };} // Not public API.#[cfg(not(feature = "extra-traits"))]#[doc(hidden)]#[macro_export]macro_rules! impl_extra_traits_for_custom_punctuation { ($ident:ident, $($tt:tt)+) => {};} // Not public API.#[doc(hidden)]#[macro_export]macro_rules! custom_punctuation_repr { ($($tt:tt)+) => { [$crate::__private::Span; 0 $(+ $crate::custom_punctuation_len!(lenient, $tt))+] };} // Not public API.#[doc(hidden)]#[macro_export]#[rustfmt::skip]macro_rules! custom_punctuation_len { ($mode:ident, &) => { 1 }; ($mode:ident, &&) => { 2 }; ($mode:ident, &=) => { 2 }; ($mode:ident, @) => { 1 }; ($mode:ident, ^) => { 1 }; ($mode:ident, ^=) => { 2 }; ($mode:ident, :) => { 1 }; ($mode:ident, ,) => { 1 }; ($mode:ident, $) => { 1 }; ($mode:ident, .) => { 1 }; ($mode:ident, ..) => { 2 }; ($mode:ident, ...) => { 3 }; ($mode:ident, ..=) => { 3 }; ($mode:ident, =) => { 1 }; ($mode:ident, ==) => { 2 }; ($mode:ident, =>) => { 2 }; ($mode:ident, >=) => { 2 }; ($mode:ident, >) => { 1 }; ($mode:ident, <-) => { 2 }; ($mode:ident, <=) => { 2 }; ($mode:ident, <) => { 1 }; ($mode:ident, -) => { 1 }; ($mode:ident, -=) => { 2 }; ($mode:ident, !=) => { 2 }; ($mode:ident, !) => { 1 }; ($mode:ident, |) => { 1 }; ($mode:ident, |=) => { 2 }; ($mode:ident, ||) => { 2 }; ($mode:ident, ::) => { 2 }; ($mode:ident, %) => { 1 }; ($mode:ident, %=) => { 2 }; ($mode:ident, +) => { 1 }; ($mode:ident, +=) => { 2 }; ($mode:ident, #) => { 1 }; ($mode:ident, ?) => { 1 }; ($mode:ident, ->) => { 2 }; ($mode:ident, ;) => { 1 }; ($mode:ident, <<) => { 2 }; ($mode:ident, <<=) => { 3 }; ($mode:ident, >>) => { 2 }; ($mode:ident, >>=) => { 3 }; ($mode:ident, /) => { 1 }; ($mode:ident, /=) => { 2 }; ($mode:ident, *) => { 1 }; ($mode:ident, *=) => { 2 }; ($mode:ident, ~) => { 1 }; (lenient, $tt:tt) => { 0 }; (strict, $tt:tt) => {{ $crate::custom_punctuation_unexpected!($tt); 0 }};} // Not public API.#[doc(hidden)]#[macro_export]macro_rules! custom_punctuation_unexpected { () => {};} // Not public API.#[doc(hidden)]#[macro_export]macro_rules! stringify_punct { ($($tt:tt)+) => { $crate::__private::concat!($($crate::__private::stringify!($tt)),+) };}
// SPDX-License-Identifier: Apache-2.0 OR MIT
/// Define a type that supports parsing and printing a multi-character symbol
/// as if it were a punctuation token.
///
/// # Usage
///
/// ```
/// syn::custom_punctuation!(LeftRightArrow, <=>);
/// ```
///
/// The generated syntax tree node supports the following operations just like
/// any built-in punctuation token.
///
/// - [Peeking] — `input.peek(LeftRightArrow)`
///
/// - [Parsing] — `input.parse::<LeftRightArrow>()?`
///
/// - [Printing] — `quote!( ... #lrarrow ... )`
///
/// - Construction from a [`Span`] — `let lrarrow = LeftRightArrow(sp)`
///
/// - Construction from multiple [`Span`] — `let lrarrow = LeftRightArrow([sp, sp, sp])`
///
/// - Field access to its spans — `let spans = lrarrow.spans`
///
/// [Peeking]: crate::parse::ParseBuffer::peek
/// [Parsing]: crate::parse::ParseBuffer::parse
/// [Printing]: quote::ToTokens
/// [`Span`]: proc_macro2::Span
///
/// # Example
///
/// ```
/// use proc_macro2::{TokenStream, TokenTree};
/// use syn::parse::{Parse, ParseStream, Peek, Result};
/// use syn::punctuated::Punctuated;
/// use syn::Expr;
///
/// syn::custom_punctuation!(PathSeparator, </>);
///
/// // expr </> expr </> expr ...
/// struct PathSegments {
/// segments: Punctuated<Expr, PathSeparator>,
/// }
///
/// impl Parse for PathSegments {
/// fn parse(input: ParseStream) -> Result<Self> {
/// let mut segments = Punctuated::new();
///
/// let first = parse_until(input, PathSeparator)?;
/// segments.push_value(syn::parse2(first)?);
///
/// while input.peek(PathSeparator) {
/// segments.push_punct(input.parse()?);
///
/// let next = parse_until(input, PathSeparator)?;
/// segments.push_value(syn::parse2(next)?);
/// }
///
/// Ok(PathSegments { segments })
/// }
/// }
///
/// fn parse_until<E: Peek>(input: ParseStream, end: E) -> Result<TokenStream> {
/// let mut tokens = TokenStream::new();
/// while !input.is_empty() && !input.peek(end) {
/// let next: TokenTree = input.parse()?;
/// tokens.extend(Some(next));
/// }
/// Ok(tokens)
/// }
///
/// fn main() {
/// let input = r#" a::b </> c::d::e "#;
/// let _: PathSegments = syn::parse_str(input).unwrap();
/// }
/// ```
#[macro_export]
macro_rules! custom_punctuation {
($ident:ident, $($tt:tt)+) => {
pub struct $ident {
#[allow(dead_code)]
pub spans: $crate::custom_punctuation_repr!($($tt)+),
}
#[doc(hidden)]
#[allow(dead_code, non_snake_case)]
pub fn $ident<__S: $crate::__private::IntoSpans<$crate::custom_punctuation_repr!($($tt)+)>>(
spans: __S,
) -> $ident {
let _validate_len = 0 $(+ $crate::custom_punctuation_len!(strict, $tt))*;
$ident {
spans: $crate::__private::IntoSpans::into_spans(spans)
}
}
const _: () = {
impl $crate::__private::Default for $ident {
fn default() -> Self {
$ident($crate::__private::Span::call_site())
}
}
$crate::impl_parse_for_custom_punctuation!($ident, $($tt)+);
$crate::impl_to_tokens_for_custom_punctuation!($ident, $($tt)+);
$crate::impl_clone_for_custom_punctuation!($ident, $($tt)+);
$crate::impl_extra_traits_for_custom_punctuation!($ident, $($tt)+);
};
};
}
// Not public API.
#[cfg(feature = "parsing")]
#[doc(hidden)]
#[macro_export]
macro_rules! impl_parse_for_custom_punctuation {
($ident:ident, $($tt:tt)+) => {
impl $crate::__private::CustomToken for $ident {
fn peek(cursor: $crate::buffer::Cursor) -> $crate::__private::bool {
$crate::__private::peek_punct(cursor, $crate::stringify_punct!($($tt)+))
}
fn display() -> &'static $crate::__private::str {
$crate::__private::concat!("`", $crate::stringify_punct!($($tt)+), "`")
}
}
impl $crate::parse::Parse for $ident {
fn parse(input: $crate::parse::ParseStream) -> $crate::parse::Result<$ident> {
let spans: $crate::custom_punctuation_repr!($($tt)+) =
$crate::__private::parse_punct(input, $crate::stringify_punct!($($tt)+))?;
Ok($ident(spans))
}
}
};
}
// Not public API.
#[cfg(not(feature = "parsing"))]
#[doc(hidden)]
#[macro_export]
macro_rules! impl_parse_for_custom_punctuation {
($ident:ident, $($tt:tt)+) => {};
}
// Not public API.
#[cfg(feature = "printing")]
#[doc(hidden)]
#[macro_export]
macro_rules! impl_to_tokens_for_custom_punctuation {
($ident:ident, $($tt:tt)+) => {
impl $crate::__private::ToTokens for $ident {
fn to_tokens(&self, tokens: &mut $crate::__private::TokenStream2) {
$crate::__private::print_punct($crate::stringify_punct!($($tt)+), &self.spans, tokens)
}
}
};
}
// Not public API.
#[cfg(not(feature = "printing"))]
#[doc(hidden)]
#[macro_export]
macro_rules! impl_to_tokens_for_custom_punctuation {
($ident:ident, $($tt:tt)+) => {};
}
// Not public API.
#[cfg(feature = "clone-impls")]
#[doc(hidden)]
#[macro_export]
macro_rules! impl_clone_for_custom_punctuation {
($ident:ident, $($tt:tt)+) => {
impl $crate::__private::Copy for $ident {}
#[allow(clippy::expl_impl_clone_on_copy)]
impl $crate::__private::Clone for $ident {
fn clone(&self) -> Self {
*self
}
}
};
}
// Not public API.
#[cfg(not(feature = "clone-impls"))]
#[doc(hidden)]
#[macro_export]
macro_rules! impl_clone_for_custom_punctuation {
($ident:ident, $($tt:tt)+) => {};
}
// Not public API.
#[cfg(feature = "extra-traits")]
#[doc(hidden)]
#[macro_export]
macro_rules! impl_extra_traits_for_custom_punctuation {
($ident:ident, $($tt:tt)+) => {
impl $crate::__private::Debug for $ident {
fn fmt(&self, f: &mut $crate::__private::Formatter) -> $crate::__private::FmtResult {
$crate::__private::Formatter::write_str(f, $crate::__private::stringify!($ident))
}
}
impl $crate::__private::Eq for $ident {}
impl $crate::__private::PartialEq for $ident {
fn eq(&self, _other: &Self) -> $crate::__private::bool {
true
}
}
impl $crate::__private::Hash for $ident {
fn hash<__H: $crate::__private::Hasher>(&self, _state: &mut __H) {}
}
};
}
// Not public API.
#[cfg(not(feature = "extra-traits"))]
#[doc(hidden)]
#[macro_export]
macro_rules! impl_extra_traits_for_custom_punctuation {
($ident:ident, $($tt:tt)+) => {};
}
// Not public API.
#[doc(hidden)]
#[macro_export]
macro_rules! custom_punctuation_repr {
($($tt:tt)+) => {
[$crate::__private::Span; 0 $(+ $crate::custom_punctuation_len!(lenient, $tt))+]
};
}
// Not public API.
#[doc(hidden)]
#[macro_export]
#[rustfmt::skip]
macro_rules! custom_punctuation_len {
($mode:ident, &) => { 1 };
($mode:ident, &&) => { 2 };
($mode:ident, &=) => { 2 };
($mode:ident, @) => { 1 };
($mode:ident, ^) => { 1 };
($mode:ident, ^=) => { 2 };
($mode:ident, :) => { 1 };
($mode:ident, ,) => { 1 };
($mode:ident, $) => { 1 };
($mode:ident, .) => { 1 };
($mode:ident, ..) => { 2 };
($mode:ident, ...) => { 3 };
($mode:ident, ..=) => { 3 };
($mode:ident, =) => { 1 };
($mode:ident, ==) => { 2 };
($mode:ident, =>) => { 2 };
($mode:ident, >=) => { 2 };
($mode:ident, >) => { 1 };
($mode:ident, <-) => { 2 };
($mode:ident, <=) => { 2 };
($mode:ident, <) => { 1 };
($mode:ident, -) => { 1 };
($mode:ident, -=) => { 2 };
($mode:ident, !=) => { 2 };
($mode:ident, !) => { 1 };
($mode:ident, |) => { 1 };
($mode:ident, |=) => { 2 };
($mode:ident, ||) => { 2 };
($mode:ident, ::) => { 2 };
($mode:ident, %) => { 1 };
($mode:ident, %=) => { 2 };
($mode:ident, +) => { 1 };
($mode:ident, +=) => { 2 };
($mode:ident, #) => { 1 };
($mode:ident, ?) => { 1 };
($mode:ident, ->) => { 2 };
($mode:ident, ;) => { 1 };
($mode:ident, <<) => { 2 };
($mode:ident, <<=) => { 3 };
($mode:ident, >>) => { 2 };
($mode:ident, >>=) => { 3 };
($mode:ident, /) => { 1 };
($mode:ident, /=) => { 2 };
($mode:ident, *) => { 1 };
($mode:ident, *=) => { 2 };
($mode:ident, ~) => { 1 };
(lenient, $tt:tt) => { 0 };
(strict, $tt:tt) => {{ $crate::custom_punctuation_unexpected!($tt); 0 }};
}
// Not public API.
#[doc(hidden)]
#[macro_export]
macro_rules! custom_punctuation_unexpected {
() => {};
}
// Not public API.
#[doc(hidden)]
#[macro_export]
macro_rules! stringify_punct {
($($tt:tt)+) => {
$crate::__private::concat!($($crate::__private::stringify!($tt)),+)
};
}