nexus_stats_core/
enums.rs

1/// Directional change or anomaly direction.
2///
3/// Used by algorithms that detect shifts, anomalies, or trends in a signal.
4#[derive(Debug, Clone, Copy, PartialEq, Eq)]
5pub enum Direction {
6    /// No directional change detected.
7    Neutral,
8    /// Upward: mean shifted up, value is high, trend is rising.
9    Rising,
10    /// Downward: mean shifted down, value is low, trend is falling.
11    Falling,
12}
13
14/// System condition state.
15///
16/// Used by algorithms that monitor health, saturation, or pressure.
17#[derive(Debug, Clone, Copy, PartialEq, Eq)]
18pub enum Condition {
19    /// Within acceptable bounds.
20    Normal,
21    /// Exceeded threshold — degraded performance.
22    Degraded,
23}
24
25/// Configuration error from building a stats primitive.
26#[derive(Debug, Clone, PartialEq, Eq)]
27pub enum ConfigError {
28    /// A required parameter was not set.
29    Missing(&'static str),
30    /// A parameter value is invalid.
31    Invalid(&'static str),
32}
33
34impl core::fmt::Display for ConfigError {
35    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
36        match self {
37            Self::Missing(param) => write!(f, "configuration error: {param} must be set"),
38            Self::Invalid(msg) => write!(f, "configuration error: {msg}"),
39        }
40    }
41}
42
43#[cfg(feature = "std")]
44impl std::error::Error for ConfigError {}
45
46/// Error returned when a streaming update receives invalid data.
47///
48/// The library distinguishes two failure categories:
49/// - **Data errors** (NaN, Inf) → returned as `Result<_, DataError>`
50/// - **Programmer errors** (wrong dimensions, out-of-range) → panic
51///
52/// The library makes no assumptions about the caller's policy.
53/// Each system has different implications for bad data.
54#[derive(Debug, Clone, Copy, PartialEq, Eq)]
55pub enum DataError {
56    /// Input contained NaN.
57    NotANumber,
58    /// Input contained positive or negative infinity.
59    Infinite,
60    /// Input contained a negative value where non-negative was required.
61    Negative,
62}
63
64impl core::fmt::Display for DataError {
65    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
66        match self {
67            Self::NotANumber => write!(f, "input contained NaN"),
68            Self::Infinite => write!(f, "input contained infinity"),
69            Self::Negative => write!(f, "input contained a negative value"),
70        }
71    }
72}
73
74#[cfg(feature = "std")]
75impl std::error::Error for DataError {}
nexus_stats_core/enums.rs

nexus_stats_core/
enums.rs
