use std::cmp::Ordering;
use std::fmt::{self, Display};
use std::hash::{Hash, Hasher};
use proc_macro2::{Span, Term};
use unicode_xid::UnicodeXID;
#[cfg_attr(feature = "extra-traits", derive(Debug))]
#[derive(Copy, Clone)]
pub struct Lifetime {
term: Term,
pub span: Span,
}
impl Lifetime {
pub fn new(term: Term, span: Span) -> Self {
let s = term.as_str();
if !s.starts_with('\'') {
panic!(
"lifetime name must start with apostrophe as in \"'a\", \
got {:?}",
s
);
}
if s == "'" {
panic!("lifetime name must not be empty");
}
fn xid_ok(s: &str) -> bool {
let mut chars = s.chars();
let first = chars.next().unwrap();
if !(UnicodeXID::is_xid_start(first) || first == '_') {
return false;
}
for ch in chars {
if !UnicodeXID::is_xid_continue(ch) {
return false;
}
}
true
}
if !xid_ok(&s[1..]) {
panic!("{:?} is not a valid lifetime name", s);
}
Lifetime {
term: term,
span: span,
}
}
}
impl Display for Lifetime {
fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
self.term.as_str().fmt(formatter)
}
}
impl PartialEq for Lifetime {
fn eq(&self, other: &Lifetime) -> bool {
self.term.as_str() == other.term.as_str()
}
}
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.term.as_str().cmp(other.term.as_str())
}
}
impl Hash for Lifetime {
fn hash<H: Hasher>(&self, h: &mut H) {
self.term.as_str().hash(h)
}
}
#[cfg(feature = "parsing")]
pub mod parsing {
use super::*;
use synom::Synom;
use buffer::Cursor;
use parse_error;
use synom::PResult;
impl Synom for Lifetime {
fn parse(input: Cursor) -> PResult<Self> {
let (span, term, rest) = match input.term() {
Some(term) => term,
_ => return parse_error(),
};
if !term.as_str().starts_with('\'') {
return parse_error();
}
Ok((
Lifetime {
term: term,
span: span,
},
rest,
))
}
fn description() -> Option<&'static str> {
Some("lifetime")
}
}
}
#[cfg(feature = "printing")]
mod printing {
use super::*;
use quote::{ToTokens, Tokens};
use proc_macro2::{TokenNode, TokenTree};
impl ToTokens for Lifetime {
fn to_tokens(&self, tokens: &mut Tokens) {
tokens.append(TokenTree {
span: self.span,
kind: TokenNode::Term(self.term),
})
}
}
}