syn_select/
selector.rs

1//! The selector for a given search, with its trait implementations.
2
3use crate::search::Search;
4use crate::Error;
5use std::fmt;
6use std::str::FromStr;
7use syn::{Ident, Item};
8
9/// The path provided by the user to search for.
10///
11/// Not all Rust paths are valid selectors; UFCS and generics are not supported.
12#[derive(Debug, Clone)]
13pub struct Selector {
14    segments: Vec<SelectorSegment>,
15}
16
17impl Selector {
18    /// Create a new `Selector` by parsing the passed-in string.
19    ///
20    /// # Usage
21    /// ```rust,edition2018
22    /// use syn_select::Selector;
23    /// let selector = Selector::try_from("hello::world").unwrap();
24    /// assert_eq!(format!("{}", selector), "hello::world".to_owned());
25    /// ```
26    pub fn try_from(s: impl AsRef<str>) -> Result<Self, Error> {
27        s.as_ref().parse()
28    }
29
30    /// Use this selector to search a file, returning the list of items that match the selector.
31    pub fn apply_to(&self, file: &syn::File) -> Vec<Item> {
32        let mut search = Search::new(self);
33        search.search_file(file);
34        search.results
35    }
36
37    pub(crate) fn part(&self, index: usize) -> &SelectorSegment {
38        &self.segments[index]
39    }
40
41    pub(crate) fn len(&self) -> usize {
42        self.segments.len()
43    }
44}
45
46impl fmt::Display for Selector {
47    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
48        write!(f, "{}", self.segments[0])?;
49        for segment in self.segments.iter().skip(1) {
50            write!(f, "::{}", segment)?;
51        }
52
53        Ok(())
54    }
55}
56
57impl FromStr for Selector {
58    type Err = Error;
59
60    fn from_str(input: &str) -> Result<Self, Self::Err> {
61        let mut segments = Vec::new();
62
63        if input.trim() == "" {
64            return Err(Error::empty_path());
65        }
66
67        for segment in input.split("::") {
68            match segment.parse() {
69                Ok(seg) => segments.push(seg),
70                Err(_) => return Err(Error::invalid_segment(segment.into())),
71            }
72        }
73
74        Ok(Selector { segments })
75    }
76}
77
78/// One segment of a selector path
79#[derive(Debug, Clone)]
80pub(crate) enum SelectorSegment {
81    /// A specific ident that must be exactly equal to match.
82    Ident(String),
83    /// A wildcard that matches any ident.
84    Wildcard,
85}
86
87impl FromStr for SelectorSegment {
88    type Err = Error;
89
90    fn from_str(input: &str) -> Result<Self, Self::Err> {
91        if input == "_" {
92            return Ok(SelectorSegment::Wildcard);
93        }
94
95        syn::parse_str::<Ident>(input)
96            .map(|ident| SelectorSegment::Ident(ident.to_string()))
97            .map_err(|_| Error::invalid_segment(input.into()))
98    }
99}
100
101impl PartialEq<Ident> for SelectorSegment {
102    fn eq(&self, other: &Ident) -> bool {
103        match self {
104            SelectorSegment::Wildcard => true,
105            SelectorSegment::Ident(ident) => other == ident,
106        }
107    }
108}
109
110impl fmt::Display for SelectorSegment {
111    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
112        match self {
113            SelectorSegment::Wildcard => "_".fmt(f),
114            SelectorSegment::Ident(ident) => ident.fmt(f),
115        }
116    }
117}
syn_select/selector.rs

syn_select/
selector.rs
