aramid/
state.rs

1/// Fiber state.
2#[derive(Debug, PartialEq)]
3#[must_use]
4pub enum State<Y, R> {
5    /// Yielded value
6    Yield(Y),
7    /// Done processing
8    Done(R),
9}
10
11impl<Y, R> State<Y, R> {
12    /// Unwrap the value wrapped in `Yield`.
13    ///
14    /// # Panics
15    ///
16    /// This function panics, if the state is `Done`.
17    ///
18    /// # Examples
19    ///
20    /// ```rust
21    /// # use aramid::State;
22    /// let state = State::<u8, ()>::Yield(9);
23    ///
24    /// assert_eq!(state.unwrap(), 9);
25    /// ```
26    #[inline]
27    pub fn unwrap(self) -> Y {
28        self.expect("should be Yield")
29    }
30
31    /// Unwrap the value wrapped in `Yield`.
32    ///
33    /// # Panics
34    ///
35    /// This function panics with a custom message, if the state is `Done`.
36    ///
37    /// # Examples
38    ///
39    /// ```rust
40    /// # use aramid::State;
41    /// let state = State::<u8, ()>::Yield(9);
42    ///
43    /// assert_eq!(state.expect("not done yet"), 9);
44    /// ```
45    #[inline]
46    pub fn expect(
47        self,
48        msg: &str,
49    ) -> Y {
50        match self {
51            State::Yield(yld) => yld,
52            State::Done(_) => panic!("{msg}"),
53        }
54    }
55
56    /// Unwrap the value wrapped in `Done`.
57    ///
58    /// # Panics
59    ///
60    /// This function panics, if the state is `Yield`.
61    ///
62    /// # Examples
63    ///
64    /// ```rust
65    /// # use aramid::State;
66    /// let state = State::<(), u8>::Done(9);
67    ///
68    /// assert_eq!(state.unwrap_done(), 9);
69    /// ```
70    #[inline]
71    pub fn unwrap_done(self) -> R {
72        self.expect_done("should be Done")
73    }
74
75    /// Unwrap the value wrapped in `Done`.
76    ///
77    /// # Panics
78    ///
79    /// This function panics with a custom message, if the state is `Yield`.
80    ///
81    /// # Examples
82    ///
83    /// ```rust
84    /// # use aramid::State;
85    /// let state = State::<(), u8>::Done(9);
86    ///
87    /// assert_eq!(state.expect_done("should be done by now"), 9);
88    /// ```
89    #[inline]
90    pub fn expect_done(
91        self,
92        msg: &str,
93    ) -> R {
94        match self {
95            State::Yield(_) => panic!("{msg}"),
96            State::Done(out) => out,
97        }
98    }
99
100    /// Return true, if the state is `Yield`, otherwise return false.
101    ///
102    /// # Examples
103    ///
104    /// ```rust
105    /// # use aramid::State;
106    /// let state = State::<u8, ()>::Yield(9);
107    ///
108    /// assert!(state.is_yield());
109    /// ```
110    pub fn is_yield(&self) -> bool {
111        match self {
112            State::Yield(_) => true,
113            State::Done(_) => false,
114        }
115    }
116
117    /// Return true, if the state is `Done`, otherwise return false.
118    ///
119    /// # Examples
120    ///
121    /// ```rust
122    /// # use aramid::State;
123    /// let state = State::<(), u8>::Done(9);
124    ///
125    /// assert!(state.is_done());
126    /// ```
127    pub fn is_done(&self) -> bool {
128        match self {
129            State::Yield(_) => false,
130            State::Done(_) => true,
131        }
132    }
133
134    /// Return the value of `Done`, or apply operator `OP` on the value of
135    /// `Yield`.
136    ///
137    /// Returns `None` if the value was `Yield`.
138    pub fn done_or<OP>(
139        &mut self,
140        f: OP,
141    ) -> Option<&mut R>
142    where
143        OP: FnOnce(&mut Y),
144    {
145        match self {
146            Self::Done(out) => Some(out),
147            Self::Yield(fbr) => {
148                f(fbr);
149                None
150            }
151        }
152    }
153
154    /// Return the result of `OP` applied on the value of `Yield`.
155    ///
156    /// Return `None` if the value is `Done`.
157    pub fn yield_and<OP, T>(
158        &mut self,
159        f: OP,
160    ) -> Option<T>
161    where
162        OP: FnOnce(&mut Y) -> T,
163    {
164        if let Self::Yield(fbr) = self {
165            Some(f(fbr))
166        } else {
167            None
168        }
169    }
170}
aramid/state.rs

aramid/
state.rs
