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use std::fmt::Write;
use serde::{self, ser::SerializeSeq, Deserialize, Deserializer, Serialize, Serializer};
#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Clone)]
pub struct Ident {
pub path: Vec<String>,
pub name: String,
}
impl Ident {
pub fn from_name<S: ToString>(name: S) -> Self {
Ident {
path: Vec::new(),
name: name.to_string(),
}
}
pub fn from_path<S: ToString>(mut path: Vec<S>) -> Self {
let name = path.pop().unwrap().to_string();
Ident {
path: path.into_iter().map(|x| x.to_string()).collect(),
name,
}
}
pub fn pop(self) -> Option<Self> {
let mut path = self.path;
path.pop().map(|name| Ident { path, name })
}
pub fn pop_front(mut self) -> (String, Option<Ident>) {
if self.path.is_empty() {
(self.name, None)
} else {
let first = self.path.remove(0);
(first, Some(self))
}
}
pub fn with_name<S: ToString>(mut self, name: S) -> Self {
self.name = name.to_string();
self
}
pub fn iter(&self) -> impl Iterator<Item = &String> {
self.path.iter().chain(std::iter::once(&self.name))
}
pub fn starts_with(&self, prefix: &Ident) -> bool {
if prefix.path.len() > self.path.len() {
return false;
}
prefix
.iter()
.zip(self.iter())
.all(|(prefix_component, self_component)| prefix_component == self_component)
}
}
impl std::fmt::Display for Ident {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
display_ident(f, self)
}
}
impl IntoIterator for Ident {
type Item = String;
type IntoIter = std::iter::Chain<
std::vec::IntoIter<std::string::String>,
std::option::IntoIter<std::string::String>,
>;
fn into_iter(self) -> Self::IntoIter {
self.path.into_iter().chain(Some(self.name))
}
}
impl std::ops::Add<Ident> for Ident {
type Output = Ident;
fn add(self, rhs: Ident) -> Self::Output {
Ident {
path: self.into_iter().chain(rhs.path).collect(),
name: rhs.name,
}
}
}
impl Serialize for Ident {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: Serializer,
{
let mut seq = serializer.serialize_seq(Some(self.path.len() + 1))?;
for part in &self.path {
seq.serialize_element(part)?;
}
seq.serialize_element(&self.name)?;
seq.end()
}
}
impl<'de> Deserialize<'de> for Ident {
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
D: Deserializer<'de>,
{
<Vec<String> as Deserialize>::deserialize(deserializer).map(Ident::from_path)
}
}
pub fn display_ident(f: &mut std::fmt::Formatter, ident: &Ident) -> Result<(), std::fmt::Error> {
for part in &ident.path {
display_ident_part(f, part)?;
f.write_char('.')?;
}
display_ident_part(f, &ident.name)?;
Ok(())
}
pub fn display_ident_part(f: &mut std::fmt::Formatter, s: &str) -> Result<(), std::fmt::Error> {
fn forbidden_start(c: char) -> bool {
!(('a'..='z').contains(&c) || matches!(c, '_' | '$'))
}
fn forbidden_subsequent(c: char) -> bool {
!(('a'..='z').contains(&c) || ('0'..='9').contains(&c) || matches!(c, '_'))
}
let needs_escape = s.is_empty()
|| s.starts_with(forbidden_start)
|| (s.len() > 1 && s.chars().skip(1).any(forbidden_subsequent));
if needs_escape {
write!(f, "`{s}`")
} else {
write!(f, "{s}")
}
}
#[test]
fn test_starts_with() {
let a = Ident::from_path(vec!["a", "b", "c"]);
let b = Ident::from_path(vec!["a", "b"]);
let c = Ident::from_path(vec!["a", "b", "c", "d"]);
let d = Ident::from_path(vec!["a", "b", "d"]);
let e = Ident::from_path(vec!["a", "c"]);
let f = Ident::from_path(vec!["b", "c"]);
assert!(a.starts_with(&b));
assert!(a.starts_with(&a));
assert!(!a.starts_with(&c));
assert!(!a.starts_with(&d));
assert!(!a.starts_with(&e));
assert!(!a.starts_with(&f));
}