105 lines
2.2 KiB
Rust
105 lines
2.2 KiB
Rust
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use std::{
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collections::BTreeMap,
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rc::Rc,
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};
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#[derive (Clone, Debug, Hash, PartialEq)]
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pub struct BogusClosure {
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pub idx: usize,
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pub upvalues: Vec <Value>,
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}
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#[derive (Clone, Debug, PartialEq)]
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pub enum Value {
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Nil,
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Boolean (bool),
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Float (f64),
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Integer (i64),
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String (Rc <String>),
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// These are all bogus, I haven't figured out how to implement
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// tables and function pointers yet
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BogusArg (Rc <Vec <String>>),
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BogusClosure (Rc <BogusClosure>),
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BogusEnv (Rc <BTreeMap <String, Value>>),
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BogusPrint,
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}
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impl Default for Value {
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fn default () -> Self {
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Self::Nil
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}
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}
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impl From <String> for Value {
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fn from (x: String) -> Self {
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Self::String (x.into ())
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}
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}
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impl From <&str> for Value {
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fn from (x: &str) -> Self {
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Self::from (String::from (x))
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}
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}
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impl From <i32> for Value {
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fn from (x: i32) -> Self {
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Self::Integer (i64::try_from (x).unwrap ())
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}
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}
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impl From <f64> for Value {
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fn from (x: f64) -> Self {
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Self::Float (x)
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}
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}
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impl std::hash::Hash for Value {
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fn hash <H: std::hash::Hasher> (&self, state: &mut H) {
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// Per https://doc.rust-lang.org/std/hash/trait.Hash.html#prefix-collisions
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[0xff].hash (state);
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match self {
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// TODO: Weaken to a Lua error
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Self::Nil => panic! ("can't hash a nil value"),
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Self::Boolean (x) => x.hash (state),
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Self::Float (x) => x.to_ne_bytes ().hash (state),
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Self::Integer (x) => x.hash (state),
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Self::String (x) => x.as_ptr ().hash (state),
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Self::BogusArg (_) => panic! ("can't hash Bogus values"),
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Self::BogusClosure (_) => panic! ("can't hash Bogus values"),
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Self::BogusEnv (_) => panic! ("can't hash Bogus values"),
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Self::BogusPrint => panic! ("can't hash Bogus values"),
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}
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}
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}
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impl Value {
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pub fn as_float (&self) -> Option <f64> {
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match self {
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Self::Float (x) => Some (*x),
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// FloatToInt isn't stable yet, so only ints in i32 space can practically be used for now
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Self::Integer (x) => f64::try_from (i32::try_from (*x).ok ()?).ok (),
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_ => None,
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}
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}
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pub fn is_truthy (&self) -> bool {
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// And this is something Lua does better than JS and Python.
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match self {
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Value::Nil => false,
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Value::Boolean (false) => false,
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_ => true,
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}
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}
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pub fn take (&mut self) -> Self {
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let mut x = Value::Nil;
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std::mem::swap (self, &mut x);
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x
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}
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}
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