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            .map(|case| case.add_product(reflection::Product::new("var", variable.to_owned())))
51    }
52}
53
54impl reflection::PredicateReflection for RegexPredicate {}
55
56impl fmt::Display for RegexPredicate {
57    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
58        let palette = crate::Palette::new(f.alternate());
59        write!(
60            f,
61            "{}.{}({})",
62            palette.var("var"),
63            palette.description("is_match"),
64            palette.expected(&self.re),
65        )
66    }
67}
68
69/// Predicate that checks for repeated patterns.
70///
71/// This is created by `predicates::str::is_match(...).count`.
72#[derive(Debug, Clone)]
73pub struct RegexMatchesPredicate {
74    re: regex::Regex,
75    count: usize,
76}
77
78impl Predicate<str> for RegexMatchesPredicate {
79    fn eval(&self, variable: &str) -> bool {
80        self.re.find_iter(variable).count() == self.count
81    }
82
83    fn find_case<'a>(&'a self, expected: bool, variable: &str) -> Option<reflection::Case<'a>> {
84        let actual_count = self.re.find_iter(variable).count();
85        let result = self.count == actual_count;
86        if result == expected {
87            Some(
88                reflection::Case::new(Some(self), result)
89                    .add_product(reflection::Product::new("var", variable.to_owned()))
90                    .add_product(reflection::Product::new("actual count", actual_count)),
91            )
92        } else {
93            None
94        }
95    }
96}
97
98impl reflection::PredicateReflection for RegexMatchesPredicate {
99    fn parameters<'a>(&'a self) -> Box<dyn Iterator<Item = reflection::Parameter<'a>> + 'a> {
100        let params = vec![reflection::Parameter::new("count", &self.count)];
101        Box::new(params.into_iter())
102    }
103}
104
105impl fmt::Display for RegexMatchesPredicate {
106    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
107        let palette = crate::Palette::new(f.alternate());
108        write!(
109            f,
110            "{}.{}({})",
111            palette.var("var"),
112            palette.description("is_match"),
113            palette.expected(&self.re),
114        )
115    }
116}
117
118/// Creates a new `Predicate` that uses a regular expression to match the string.
119///
120/// # Examples
121///
122/// ```
123/// use predicates::prelude::*;
124///
125/// let predicate_fn = predicate::str::is_match("^Hello.*$").unwrap();
126/// assert_eq!(true, predicate_fn.eval("Hello World"));
127/// assert_eq!(false, predicate_fn.eval("Food World"));
128/// ```
129pub fn is_match<S>(pattern: S) -> Result<RegexPredicate, RegexError>
130where
131    S: AsRef<str>,
132{
133    regex::Regex::new(pattern.as_ref()).map(|re| RegexPredicate { re })
134}
predicates/str/regex.rs

predicates/str/
regex.rs
