predicates/str/
regex.rs

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1// Copyright (c) 2018 The predicates-rs Project Developers.
2//
3// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
4// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
5// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
6// option. This file may not be copied, modified, or distributed
7// except according to those terms.
8
9use std::fmt;
10
11use crate::reflection;
12use crate::utils;
13use crate::Predicate;
14
15/// An error that occurred during parsing or compiling a regular expression.
16pub type RegexError = regex::Error;
17
18/// Predicate that uses regex matching
19///
20/// This is created by the `predicate::str::is_match`.
21#[derive(Debug, Clone)]
22pub struct RegexPredicate {
23    re: regex::Regex,
24}
25
26impl RegexPredicate {
27    /// Require a specific count of matches.
28    ///
29    /// # Examples
30    ///
31    /// ```
32    /// use predicates::prelude::*;
33    ///
34    /// let predicate_fn = predicate::str::is_match("T[a-z]*").unwrap().count(3);
35    /// assert_eq!(true, predicate_fn.eval("One Two Three Two One"));
36    /// assert_eq!(false, predicate_fn.eval("One Two Three"));
37    /// ```
38    pub fn count(self, count: usize) -> RegexMatchesPredicate {
39        RegexMatchesPredicate { re: self.re, count }
40    }
41}
42
43impl Predicate<str> for RegexPredicate {
44    fn eval(&self, variable: &str) -> bool {
45        self.re.is_match(variable)
46    }
47
48    fn find_case<'a>(&'a self, expected: bool, variable: &str) -> Option<reflection::Case<'a>> {
49        utils::default_find_case(self, expected, variable)
50    }
51}
52
53impl reflection::PredicateReflection for RegexPredicate {}
54
55impl fmt::Display for RegexPredicate {
56    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
57        write!(f, "var.is_match({})", self.re)
58    }
59}
60
61/// Predicate that checks for repeated patterns.
62///
63/// This is created by `predicates::str::is_match(...).count`.
64#[derive(Debug, Clone)]
65pub struct RegexMatchesPredicate {
66    re: regex::Regex,
67    count: usize,
68}
69
70impl Predicate<str> for RegexMatchesPredicate {
71    fn eval(&self, variable: &str) -> bool {
72        self.re.find_iter(variable).count() == self.count
73    }
74
75    fn find_case<'a>(&'a self, expected: bool, variable: &str) -> Option<reflection::Case<'a>> {
76        let actual_count = self.re.find_iter(variable).count();
77        let result = self.count == actual_count;
78        if result == expected {
79            Some(
80                reflection::Case::new(Some(self), result)
81                    .add_product(reflection::Product::new("actual count", actual_count)),
82            )
83        } else {
84            None
85        }
86    }
87}
88
89impl reflection::PredicateReflection for RegexMatchesPredicate {
90    fn parameters<'a>(&'a self) -> Box<dyn Iterator<Item = reflection::Parameter<'a>> + 'a> {
91        let params = vec![reflection::Parameter::new("count", &self.count)];
92        Box::new(params.into_iter())
93    }
94}
95
96impl fmt::Display for RegexMatchesPredicate {
97    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
98        write!(f, "var.is_match({})", self.re)
99    }
100}
101
102/// Creates a new `Predicate` that uses a regular expression to match the string.
103///
104/// # Examples
105///
106/// ```
107/// use predicates::prelude::*;
108///
109/// let predicate_fn = predicate::str::is_match("^Hel.o.*$").unwrap();
110/// assert_eq!(true, predicate_fn.eval("Hello World"));
111/// assert_eq!(false, predicate_fn.eval("Food World"));
112/// ```
113pub fn is_match<S>(pattern: S) -> Result<RegexPredicate, RegexError>
114where
115    S: AsRef<str>,
116{
117    regex::Regex::new(pattern.as_ref()).map(|re| RegexPredicate { re })
118}
predicates/str/regex.rs

predicates/str/
regex.rs
