51 lines
1.3 KiB
Rust
51 lines
1.3 KiB
Rust
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//! Provides implementation for helpers used in parsing `TokenStream`s where the
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//! data ultimately does not care about its `Span` information, but it is useful
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//! during intermediate processing.
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use proc_macro2::Span;
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use std::ops::Deref;
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use syn::parse::{Parse, ParseStream, Result as ParseResult};
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/// Trait that abstracts functionality for inner data that can be parsed and
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/// wrapped with a specific `Span`.
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pub trait ParseInner: Sized {
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fn spanned_parse(input: ParseStream) -> ParseResult<(Span, Self)>;
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}
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impl<T: Parse> ParseInner for T {
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fn spanned_parse(input: ParseStream) -> ParseResult<(Span, Self)> {
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Ok((input.span(), T::parse(input)?))
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}
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}
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impl<T: ParseInner> Parse for Spanned<T> {
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fn parse(input: ParseStream) -> ParseResult<Self> {
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let (span, value) = T::spanned_parse(input)?;
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Ok(Spanned(span, value))
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}
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}
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/// A struct that captures `Span` information for inner parsable data.
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#[cfg_attr(test, derive(Clone, Debug))]
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pub struct Spanned<T>(Span, T);
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impl<T> Spanned<T> {
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/// Retrieves the captured `Span` information for the parsed data.
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pub fn span(&self) -> Span {
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self.0
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}
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/// Retrieves the inner data.
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pub fn into_inner(self) -> T {
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self.1
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}
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}
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impl<T> Deref for Spanned<T> {
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type Target = T;
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fn deref(&self) -> &Self::Target {
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&self.1
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}
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}
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