swc_ecma_utils/value.rs
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use std::ops::Not;
use self::Value::{Known, Unknown};
/// Runtime value.
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub enum Value<T> {
Known(T),
/// Not determined at compile time.`
Unknown,
}
/// Type of value.
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub enum Type {
Undefined,
Null,
Bool,
Str,
Symbol,
Num,
Obj,
}
impl Value<Type> {
pub fn casted_to_number_on_add(self) -> bool {
match self {
Known(Type::Bool) | Known(Type::Null) | Known(Type::Num) | Known(Type::Undefined) => {
true
}
_ => false,
}
}
}
/// Value could not be determined
pub struct UnknownError;
// impl<T> Try for Value<T> {
// type Ok = T;
// type Error = UnknownError;
// fn from_ok(t: T) -> Self {
// Known(t)
// }
// fn from_error(_: UnknownError) -> Self {
// Unknown
// }
// fn into_result(self) -> Result<T, UnknownError> {
// match self {
// Known(t) => Ok(t),
// Unknown => Err(UnknownError),
// }
// }
// }
impl<T> Value<T> {
pub fn into_result(self) -> Result<T, UnknownError> {
match self {
Known(v) => Ok(v),
Unknown => Err(UnknownError),
}
}
}
impl<T> Value<T> {
/// Returns true if the value is not known.
pub fn is_unknown(&self) -> bool {
matches!(*self, Unknown)
}
/// Returns true if the value is known.
pub fn is_known(&self) -> bool {
matches!(*self, Known(..))
}
}
impl Value<bool> {
pub fn and(self, other: Self) -> Self {
match self {
Known(true) => other,
Known(false) => Known(false),
Unknown => match other {
Known(false) => Known(false),
_ => Unknown,
},
}
}
pub fn or(self, other: Self) -> Self {
match self {
Known(true) => Known(true),
Known(false) => other,
Unknown => match other {
Known(true) => Known(true),
_ => Unknown,
},
}
}
}
impl Not for Value<bool> {
type Output = Self;
fn not(self) -> Self {
match self {
Value::Known(b) => Value::Known(!b),
Value::Unknown => Value::Unknown,
}
}
}