75 lines
1.8 KiB
Rust
75 lines
1.8 KiB
Rust
use super::*;
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/// A value that can be automatically determined.
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#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
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pub enum Smart<T> {
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/// The value should be determined smartly based on the circumstances.
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Auto,
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/// A specific value.
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Custom(T),
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}
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impl<T> Smart<T> {
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/// Whether the value is `Auto`.
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pub fn is_auto(&self) -> bool {
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matches!(self, Self::Auto)
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}
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/// Whether this holds a custom value.
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pub fn is_custom(&self) -> bool {
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matches!(self, Self::Custom(_))
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}
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/// Map the contained custom value with `f`.
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pub fn map<F, U>(self, f: F) -> Smart<U>
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where
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F: FnOnce(T) -> U,
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{
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match self {
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Self::Auto => Smart::Auto,
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Self::Custom(x) => Smart::Custom(f(x)),
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}
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}
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/// Keeps `self` if it contains a custom value, otherwise returns `other`.
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pub fn or(self, other: Smart<T>) -> Self {
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match self {
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Self::Custom(x) => Self::Custom(x),
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Self::Auto => other,
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}
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}
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/// Returns the contained custom value or a provided default value.
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pub fn unwrap_or(self, default: T) -> T {
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match self {
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Self::Auto => default,
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Self::Custom(x) => x,
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}
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}
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/// Returns the contained custom value or computes a default value.
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pub fn unwrap_or_else<F>(self, f: F) -> T
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where
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F: FnOnce() -> T,
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{
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match self {
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Self::Auto => f(),
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Self::Custom(x) => x,
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}
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}
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/// Returns the contained custom value or the default value.
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pub fn unwrap_or_default(self) -> T
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where
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T: Default,
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{
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self.unwrap_or_else(T::default)
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}
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}
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impl<T> Default for Smart<T> {
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fn default() -> Self {
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Self::Auto
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}
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}
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