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|
use proc_macro::{Ident, TokenStream, TokenTree};
use std::iter;
macro_rules! quote {
() => {
::proc_macro::TokenStream::new()
};
($($tt:tt)*) => {{
let mut tokens = ::proc_macro::TokenStream::new();
quote_each_token!(tokens $($tt)*);
tokens
}};
}
macro_rules! quote_each_token {
($tokens:ident # $var:ident $($rest:tt)*) => {
$crate::quote::Tokens::extend(&mut $tokens, &$var);
quote_each_token!($tokens $($rest)*);
};
($tokens:ident $ident:ident $($rest:tt)*) => {
<::proc_macro::TokenStream as ::std::iter::Extend<_>>::extend(
&mut $tokens,
::std::iter::once(
::proc_macro::TokenTree::Ident(
::proc_macro::Ident::new(
stringify!($ident),
::proc_macro::Span::call_site(),
),
),
),
);
quote_each_token!($tokens $($rest)*);
};
($tokens:ident ( $($inner:tt)* ) $($rest:tt)*) => {
<::proc_macro::TokenStream as ::std::iter::Extend<_>>::extend(
&mut $tokens,
::std::iter::once(
::proc_macro::TokenTree::Group(
::proc_macro::Group::new(
::proc_macro::Delimiter::Parenthesis,
quote!($($inner)*),
),
),
),
);
quote_each_token!($tokens $($rest)*);
};
($tokens:ident [ $($inner:tt)* ] $($rest:tt)*) => {
<::proc_macro::TokenStream as ::std::iter::Extend<_>>::extend(
&mut $tokens,
::std::iter::once(
::proc_macro::TokenTree::Group(
::proc_macro::Group::new(
::proc_macro::Delimiter::Bracket,
quote!($($inner)*),
),
),
),
);
quote_each_token!($tokens $($rest)*);
};
($tokens:ident { $($inner:tt)* } $($rest:tt)*) => {
<::proc_macro::TokenStream as ::std::iter::Extend<_>>::extend(
&mut $tokens,
::std::iter::once(
::proc_macro::TokenTree::Group(
::proc_macro::Group::new(
::proc_macro::Delimiter::Brace,
quote!($($inner)*),
),
),
),
);
quote_each_token!($tokens $($rest)*);
};
($tokens:ident $punct:tt $($rest:tt)*) => {
<::proc_macro::TokenStream as ::std::iter::Extend<_>>::extend(
&mut $tokens,
stringify!($punct).parse::<::proc_macro::TokenStream>(),
);
quote_each_token!($tokens $($rest)*);
};
($tokens:ident) => {};
}
pub trait Tokens {
fn extend(tokens: &mut TokenStream, var: &Self);
}
impl Tokens for Ident {
fn extend(tokens: &mut TokenStream, var: &Self) {
tokens.extend(iter::once(TokenTree::Ident(var.clone())));
}
}
impl Tokens for TokenStream {
fn extend(tokens: &mut TokenStream, var: &Self) {
tokens.extend(var.clone());
}
}
impl<T: Tokens> Tokens for Option<T> {
fn extend(tokens: &mut TokenStream, var: &Self) {
if let Some(var) = var {
T::extend(tokens, var);
}
}
}
impl<T: Tokens> Tokens for &T {
fn extend(tokens: &mut TokenStream, var: &Self) {
T::extend(tokens, var);
}
}
|
