impl Hash for Value

src/loader.rs

@@ -18,14 +18,14 @@ pub (crate) fn compile_bytecode (source: Vec <u8>) -> Vec <u8> {
 		},
 	};
 	
-	let mut child = Command::new ("luac")
+	let mut child = Command::new ("luac5.4")
 	.arg ("-o") // Output to...
 	.arg ("-")  // Standard output
 	.arg ("-")  // Input from standard input
 	.stdin (Stdio::piped ())
 	.stdout (Stdio::piped ())
 	.spawn ()
-	.expect ("failed to execute `luac`. Is Lua installed?");
+	.expect ("failed to execute `luac5.4`. Is Lua installed?");
 	
 	let mut stdin = child.stdin.take ().expect ("failed to get stdin");
 	std::thread::spawn (move || {

src/state.rs

@@ -65,7 +65,7 @@ pub enum Instruction {
 	VarArgPrep (i32),
 }
 
-#[derive (Clone, Debug, PartialEq)]
+#[derive (Clone, Debug, Hash, PartialEq)]
 pub struct BogusClosure {
 	idx: usize,
 	upvalues: Vec <Value>,
@@ -118,6 +118,26 @@ impl From <f64> for Value {
 	}
 }
 
+impl std::hash::Hash for Value {
+	fn hash <H: std::hash::Hasher> (&self, state: &mut H) {
+		// Per https://doc.rust-lang.org/std/hash/trait.Hash.html#prefix-collisions
+		[0xff].hash (state);
+		
+		match self {
+			// TODO: Weaken to a Lua error
+			Self::Nil => panic! ("can't hash a nil value"),
+			Self::Boolean (x) => x.hash (state),
+			Self::Float (x) => x.to_ne_bytes ().hash (state),
+			Self::Integer (x) => x.hash (state),
+			Self::String (x) => x.as_ptr ().hash (state),
+			Self::BogusArg (_) => panic! ("can't hash Bogus values"),
+			Self::BogusClosure (_) => panic! ("can't hash Bogus values"),
+			Self::BogusEnv (_) => panic! ("can't hash Bogus values"),
+			Self::BogusPrint => panic! ("can't hash Bogus values"),
+		}
+	}
+}
+
 impl Value {
 	fn as_float (&self) -> Option <f64> {
 		match self {