56 lines
1.7 KiB
Rust
56 lines
1.7 KiB
Rust
use proc_macro::{Delimiter, Group, Ident, Literal, Punct, Spacing, Span, TokenStream, TokenTree};
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use std::fmt::Display;
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use std::iter::FromIterator;
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pub type Result<T, E = Error> = std::result::Result<T, E>;
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pub struct Error {
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begin: Span,
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end: Span,
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msg: String,
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}
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impl Error {
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pub fn new(span: Span, msg: impl Display) -> Self {
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Self::new2(span, span, msg)
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}
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pub fn new2(begin: Span, end: Span, msg: impl Display) -> Self {
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Error {
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begin,
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end,
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msg: msg.to_string(),
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}
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}
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pub fn group(group: Group, msg: impl Display) -> Self {
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let mut iter = group.stream().into_iter();
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let delimiter = group.span();
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let begin = iter.next().map_or(delimiter, |t| t.span());
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let end = iter.last().map_or(begin, |t| t.span());
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Self::new2(begin, end, msg)
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}
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pub fn into_compile_error(self) -> TokenStream {
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// compile_error! { $msg }
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TokenStream::from_iter(vec![
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TokenTree::Ident(Ident::new("compile_error", self.begin)),
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TokenTree::Punct({
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let mut punct = Punct::new('!', Spacing::Alone);
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punct.set_span(self.begin);
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punct
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}),
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TokenTree::Group({
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let mut group = Group::new(Delimiter::Brace, {
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TokenStream::from_iter(vec![TokenTree::Literal({
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let mut string = Literal::string(&self.msg);
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string.set_span(self.end);
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string
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})])
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});
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group.set_span(self.end);
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group
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}),
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])
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}
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}
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