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Diffstat (limited to 'vendor/syn/src/lifetime.rs')
-rw-r--r-- | vendor/syn/src/lifetime.rs | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/vendor/syn/src/lifetime.rs b/vendor/syn/src/lifetime.rs new file mode 100644 index 0000000..29f4cfd --- /dev/null +++ b/vendor/syn/src/lifetime.rs @@ -0,0 +1,156 @@ +use proc_macro2::{Ident, Span}; +use std::cmp::Ordering; +use std::fmt::{self, Display}; +use std::hash::{Hash, Hasher}; + +#[cfg(feature = "parsing")] +use crate::lookahead; + +/// A Rust lifetime: `'a`. +/// +/// Lifetime names must conform to the following rules: +/// +/// - Must start with an apostrophe. +/// - Must not consist of just an apostrophe: `'`. +/// - Character after the apostrophe must be `_` or a Unicode code point with +/// the XID_Start property. +/// - All following characters must be Unicode code points with the XID_Continue +/// property. +pub struct Lifetime { + pub apostrophe: Span, + pub ident: Ident, +} + +impl Lifetime { + /// # Panics + /// + /// Panics if the lifetime does not conform to the bulleted rules above. + /// + /// # Invocation + /// + /// ``` + /// # use proc_macro2::Span; + /// # use syn::Lifetime; + /// # + /// # fn f() -> Lifetime { + /// Lifetime::new("'a", Span::call_site()) + /// # } + /// ``` + pub fn new(symbol: &str, span: Span) -> Self { + if !symbol.starts_with('\'') { + panic!( + "lifetime name must start with apostrophe as in \"'a\", got {:?}", + symbol + ); + } + + if symbol == "'" { + panic!("lifetime name must not be empty"); + } + + if !crate::ident::xid_ok(&symbol[1..]) { + panic!("{:?} is not a valid lifetime name", symbol); + } + + Lifetime { + apostrophe: span, + ident: Ident::new(&symbol[1..], span), + } + } + + pub fn span(&self) -> Span { + self.apostrophe + .join(self.ident.span()) + .unwrap_or(self.apostrophe) + } + + pub fn set_span(&mut self, span: Span) { + self.apostrophe = span; + self.ident.set_span(span); + } +} + +impl Display for Lifetime { + fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result { + "'".fmt(formatter)?; + self.ident.fmt(formatter) + } +} + +impl Clone for Lifetime { + fn clone(&self) -> Self { + Lifetime { + apostrophe: self.apostrophe, + ident: self.ident.clone(), + } + } +} + +impl PartialEq for Lifetime { + fn eq(&self, other: &Lifetime) -> bool { + self.ident.eq(&other.ident) + } +} + +impl Eq for Lifetime {} + +impl PartialOrd for Lifetime { + fn partial_cmp(&self, other: &Lifetime) -> Option<Ordering> { + Some(self.cmp(other)) + } +} + +impl Ord for Lifetime { + fn cmp(&self, other: &Lifetime) -> Ordering { + self.ident.cmp(&other.ident) + } +} + +impl Hash for Lifetime { + fn hash<H: Hasher>(&self, h: &mut H) { + self.ident.hash(h); + } +} + +#[cfg(feature = "parsing")] +pub_if_not_doc! { + #[doc(hidden)] + #[allow(non_snake_case)] + pub fn Lifetime(marker: lookahead::TokenMarker) -> Lifetime { + match marker {} + } +} + +#[cfg(feature = "parsing")] +pub(crate) mod parsing { + use super::*; + use crate::parse::{Parse, ParseStream, Result}; + + #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))] + impl Parse for Lifetime { + fn parse(input: ParseStream) -> Result<Self> { + input.step(|cursor| { + cursor + .lifetime() + .ok_or_else(|| cursor.error("expected lifetime")) + }) + } + } +} + +#[cfg(feature = "printing")] +mod printing { + use super::*; + use proc_macro2::{Punct, Spacing, TokenStream}; + use quote::{ToTokens, TokenStreamExt}; + + #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))] + impl ToTokens for Lifetime { + fn to_tokens(&self, tokens: &mut TokenStream) { + let mut apostrophe = Punct::new('\'', Spacing::Joint); + apostrophe.set_span(self.apostrophe); + tokens.append(apostrophe); + self.ident.to_tokens(tokens); + } + } +} |