predicates/
name.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
9//! Name predicate expressions.
10
11use std::fmt;
12use std::marker::PhantomData;
13
14use crate::reflection;
15use crate::Predicate;
16
17/// Augment an existing predicate with a name.
18///
19/// This is created by the `PredicateNameExt::name` function.
20#[derive(Debug, Clone, Copy, PartialEq, Eq)]
21pub struct NamePredicate<M, Item>
22where
23    M: Predicate<Item>,
24    Item: ?Sized,
25{
26    inner: M,
27    name: &'static str,
28    _phantom: PhantomData<Item>,
29}
30
31unsafe impl<M, Item> Send for NamePredicate<M, Item>
32where
33    M: Predicate<Item> + Send,
34    Item: ?Sized,
35{
36}
37
38unsafe impl<M, Item> Sync for NamePredicate<M, Item>
39where
40    M: Predicate<Item> + Sync,
41    Item: ?Sized,
42{
43}
44
45impl<M, Item> Predicate<Item> for NamePredicate<M, Item>
46where
47    M: Predicate<Item>,
48    Item: ?Sized,
49{
50    fn eval(&self, item: &Item) -> bool {
51        self.inner.eval(item)
52    }
53
54    fn find_case<'a>(&'a self, expected: bool, variable: &Item) -> Option<reflection::Case<'a>> {
55        self.inner
56            .find_case(expected, variable)
57            .map(|child_case| reflection::Case::new(Some(self), expected).add_child(child_case))
58    }
59}
60
61impl<M, Item> reflection::PredicateReflection for NamePredicate<M, Item>
62where
63    M: Predicate<Item>,
64    Item: ?Sized,
65{
66    fn children<'a>(&'a self) -> Box<dyn Iterator<Item = reflection::Child<'a>> + 'a> {
67        let params = vec![reflection::Child::new(self.name, &self.inner)];
68        Box::new(params.into_iter())
69    }
70}
71
72impl<M, Item> fmt::Display for NamePredicate<M, Item>
73where
74    M: Predicate<Item>,
75    Item: ?Sized,
76{
77    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
78        let palette = crate::Palette::new(f.alternate());
79        write!(f, "{}", palette.description(self.name))
80    }
81}
82
83/// `Predicate` extension that adds naming predicate expressions.
84pub trait PredicateNameExt<Item: ?Sized>
85where
86    Self: Predicate<Item>,
87{
88    /// Name a predicate expression.
89    ///
90    /// # Examples
91    ///
92    /// ```
93    /// use predicates::prelude::*;
94    ///
95    /// let predicate_fn = predicate::str::is_empty().not().name("non-empty");
96    /// println!("{}", predicate_fn);
97    /// ```
98    fn name(self, name: &'static str) -> NamePredicate<Self, Item>
99    where
100        Self: Sized,
101    {
102        NamePredicate {
103            inner: self,
104            name,
105            _phantom: PhantomData,
106        }
107    }
108}
109
110impl<P, Item> PredicateNameExt<Item> for P
111where
112    P: Predicate<Item>,
113    Item: ?Sized,
114{
115}
predicates/name.rs

predicates/
name.rs
