1 files changed, 140 insertions, 0 deletions
diff --git a/syn/src/lifetime.rs b/syn/src/lifetime.rs
new file mode 100644
index 0000000..d51c48e
--- /dev/null
+++ b/syn/src/lifetime.rs
@@ -0,0 +1,140 @@
+use std::cmp::Ordering;
+use std::fmt::{self, Display};
+use std::hash::{Hash, Hasher};
+
+use proc_macro2::{Ident, Span};
+
+#[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.
+///
+/// *This type is available if Syn is built with the `"derive"` or `"full"`
+/// feature.*
+#[cfg_attr(feature = "extra-traits", derive(Debug))]
+#[derive(Clone)]
+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),
+        }
+    }
+}
+
+impl Display for Lifetime {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        "'".fmt(formatter)?;
+        self.ident.fmt(formatter)
+    }
+}
+
+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")]
+#[doc(hidden)]
+#[allow(non_snake_case)]
+pub fn Lifetime(marker: lookahead::TokenMarker) -> Lifetime {
+    match marker {}
+}
+
+#[cfg(feature = "parsing")]
+pub mod parsing {
+    use super::*;
+
+    use crate::parse::{Parse, ParseStream, Result};
+
+    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};
+
+    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);
+        }
+    }
+}