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#![warn(clippy::pedantic)]
#![deny(missing_docs)]
macro_rules! once {
(($($tts:tt)*) $($tail:tt)*) => {
$($tts)*
};
}
macro_rules! impl_via_trait {
(
$(
$(#$trait_attr:tt)*
impl $trait:ident for $type:ident {
$(#$first_attr:tt)*
$(type $types:ident = $type_assignment:ty; $(#$type_attr:tt)* )*
$(fn $function:ident($($args:tt)*) $(-> $ret:ty)? { $($stmts:tt)* } $(#$fn_attr:tt)* )*
}
)+
) => {
once!($(($(#$trait_attr)* pub trait $trait {
$(#$first_attr)*
$(type $types; $(#$type_attr)*)*
$(fn $function($($args)*) $(-> $ret)?; $(#$fn_attr)*)*
}))?);
$(#[cfg(feature = "proc-macro2")]
const _:() = {
use proc_macro2::*;
impl $trait for $type {
$(type $types = $type_assignment;)*
$(fn $function($($args)*) $(-> $ret)? {
$($stmts)*
})*
}
};
#[cfg(use_proc_macro)]
const _:() = {
use proc_macro::*;
impl $trait for $type {
$(fn $function($($args)*) $(-> $ret)? {
$($stmts)*
})*
}
};)+
};
}
impl_via_trait! {
#[cfg_attr(feature = "proc-macro2", doc = "[`proc_macro2::TokenStream`]")]
#[cfg_attr(all(proc_macro, feature = "proc-macro2"), doc = "and")]
#[cfg_attr(proc_macro, doc = "[`proc_macro::TokenStream`]")]
#[cfg_attr(not(any(proc_macro, feature = "proc-macro2")), doc = "`proc_macro::TokenStream`")]
impl TokenStreamExt for TokenStream {
type TokenTree = TokenTree;
fn push(&mut self, token: Self::TokenTree) {
self.extend(std::iter::once(token))
}
}
}
macro_rules! token_tree_ext {
($($a:literal, $token:literal, $is:ident, $as:ident, $variant:ident);+$(;)?) => {
impl_via_trait! {
#[cfg_attr(feature = "proc-macro2", doc = "[`proc_macro2::TokenTree`]")]
#[cfg_attr(all(proc_macro, feature = "proc-macro2"), doc = "and")]
#[cfg_attr(proc_macro, doc = "[`proc_macro::TokenTree`]")]
#[cfg_attr(not(any(proc_macro, feature = "proc-macro2")), doc = "`proc_macro::TokenTree`")]
impl TokenTreeExt for TokenTree {
$(
#[doc = concat!(stringify!($variant), " of this TokenTree, necessary to support both TokenTrees")]
type $variant = $variant;
)*
$(
#[doc = concat!("Tests if the token tree is ", $a, " ", $token, ".")]
fn $is(&self) -> bool {
matches!(self, Self::$variant(_))
}
#[doc = concat!("Get the `", stringify!($variant), "` inside this token tree, or [`None`] if it isn't ", $a, " ", $token, ".")]
fn $as(self) -> Option<<Self as TokenTreeExt>::$variant> {
if let Self::$variant(inner) = self {
Some(inner)
} else {
None
}
}
)*
}
}
};
}
token_tree_ext!(
"a", "group", is_group, group, Group;
"an", "ident", is_ident, ident, Ident;
"a", "punctuation", is_punct, punct, Punct;
"a", "literal", is_literal, literal, Literal;
);
macro_rules! punctuations {
($($char:literal as $name:ident),*) => {
impl_via_trait!{
impl TokenTreePunct for TokenTree {
$(#[doc = concat!("Tests if the token is `", $char, "`")]
fn $name(&self) -> bool {
matches!(self, TokenTree::Punct(punct) if punct.as_char() == $char)
})*
}
impl TokenTreePunct for Punct {
$(fn $name(&self) -> bool {
self.as_char() == $char
})*
}
}
};
}
punctuations![
'=' as is_equals,
'<' as is_less_than,
'>' as is_greater_than,
'!' as is_exclamation,
'~' as is_tilde,
'+' as is_plus,
'-' as is_minus,
'*' as is_asterix, '/' as is_slash,
'%' as is_percent,
'^' as is_caret,
'&' as is_and,
'|' as is_pipe,
'@' as is_at,
'.' as is_dot,
',' as is_comma,
';' as is_semi,
':' as is_colon,
'#' as is_pound,
'$' as is_dollar,
'?' as is_question,
'\'' as is_quote ];
#[cfg(all(test, feature = "proc-macro2"))]
mod test {
use proc_macro2::{Punct, Spacing, TokenTree};
use quote::quote;
use super::*;
#[test]
fn punctuation() {
let mut tokens = quote! {=<>!$~+-*/%^|@.,;:#$?'a}.into_iter();
assert!(tokens.next().unwrap().is_equals());
assert!(tokens.next().unwrap().is_less_than());
assert!(tokens.next().unwrap().is_greater_than());
assert!(tokens.next().unwrap().is_exclamation());
assert!(tokens.next().unwrap().is_dollar());
assert!(tokens.next().unwrap().is_tilde());
assert!(tokens.next().unwrap().is_plus());
assert!(tokens.next().unwrap().is_minus());
assert!(tokens.next().unwrap().is_asterix());
assert!(tokens.next().unwrap().is_slash());
assert!(tokens.next().unwrap().is_percent());
assert!(tokens.next().unwrap().is_caret());
assert!(tokens.next().unwrap().is_pipe());
assert!(tokens.next().unwrap().is_at());
assert!(tokens.next().unwrap().is_dot());
assert!(tokens.next().unwrap().is_comma());
assert!(tokens.next().unwrap().is_semi());
assert!(tokens.next().unwrap().is_colon());
assert!(tokens.next().unwrap().is_pound());
assert!(tokens.next().unwrap().is_dollar());
assert!(tokens.next().unwrap().is_question());
assert!(tokens.next().unwrap().is_quote());
}
#[test]
fn token_stream_ext() {
let mut tokens = quote!(a);
tokens.push(TokenTree::Punct(Punct::new(',', Spacing::Alone)));
assert_eq!(tokens.to_string(), "a ,");
}
#[test]
fn token_tree_ext() {
let mut tokens = quote!({group} ident + "literal").into_iter().peekable();
assert!(tokens.peek().unwrap().is_group());
assert_eq!(
tokens.next().unwrap().group().unwrap().to_string(),
"{ group }"
);
assert!(tokens.peek().unwrap().is_ident());
assert_eq!(tokens.next().unwrap().ident().unwrap().to_string(), "ident");
assert!(tokens.peek().unwrap().is_punct());
assert_eq!(tokens.next().unwrap().punct().unwrap().to_string(), "+");
assert!(tokens.peek().unwrap().is_literal());
assert_eq!(
tokens.next().unwrap().literal().unwrap().to_string(),
"\"literal\""
);
}
}