Add test for equality chain

dust-lang/src/chunk.rs

@@ -399,10 +399,10 @@ impl<'a> ChunkDisassembler<'a> {
             let bytecode = u32::from(instruction);
 
             let instruction_display = if let Some(info) = info_option {
-                format!("{index:<5} {bytecode:<8X} {operation:15} {info:30} {position:8}")
+                format!("{index:<5} {bytecode:<08X} {operation:15} {info:30} {position:8}")
             } else {
                 format!(
-                    "{index:<5} {bytecode:<8X} {operation:15} {:30} {position:8}",
+                    "{index:<5} {bytecode:<08X} {operation:15} {:30} {position:8}",
                     " "
                 )
             };

dust-lang/src/parser/mod.rs

@@ -477,9 +477,31 @@ impl<'src> Parser<'src> {
     }
 
     fn parse_comparison_binary(&mut self) -> Result<(), ParseError> {
+        let (previous_booleans, equal_argument) = if let [Some(Operation::LoadBoolean), Some(Operation::LoadBoolean), Some(Operation::Jump), Some(Operation::Equal)] =
+            self.chunk.get_last_n_operations()
+        {
+            self.increment_register()?;
+
+            let load_booleans = (
+                self.chunk.pop_instruction(self.current_position)?,
+                self.chunk.pop_instruction(self.current_position)?,
+            );
+
+            let (jump, jump_position) = self.chunk.pop_instruction(self.current_position)?;
+            let (equal, equal_position) = self.chunk.pop_instruction(self.current_position)?;
+            let equal_argument = equal.second_argument();
+            let is_constant = equal.second_argument_is_constant();
+
+            self.emit_instruction(equal, equal_position);
+            self.emit_instruction(jump, jump_position);
+
+            (Some(load_booleans), Some((equal_argument, is_constant)))
+        } else {
+            (None, None)
+        };
+
         let (left_instruction, left_position) =
             self.chunk.pop_instruction(self.current_position)?;
-
         let (push_back_left, left_is_constant, left) =
             self.handle_binary_argument(&left_instruction)?;
 
@@ -514,13 +536,18 @@ impl<'src> Parser<'src> {
 
         let (right_instruction, right_position) =
             self.chunk.pop_instruction(self.current_position)?;
-
         let (push_back_right, right_is_constant, right) =
             self.handle_binary_argument(&right_instruction)?;
 
         instruction.set_second_argument(right);
 
-        if left_is_constant {
+        if let Some((equal_argument, is_constant)) = equal_argument {
+            instruction.set_first_argument(equal_argument);
+
+            if is_constant {
+                instruction.set_first_argument_to_constant();
+            }
+        } else if left_is_constant {
             instruction.set_first_argument_to_constant();
         }
 
@@ -528,8 +555,23 @@ impl<'src> Parser<'src> {
             instruction.set_second_argument_to_constant();
         }
 
+        if push_back_left {
+            self.emit_instruction(left_instruction, left_position);
+        }
+
+        if push_back_right {
+            self.emit_instruction(right_instruction, right_position);
+        }
+
         self.emit_instruction(instruction, operator_position);
         self.emit_instruction(Instruction::jump(1, true), operator_position);
+
+        if let Some(((left_boolean, left_position), (right_boolean, right_position))) =
+            previous_booleans
+        {
+            self.emit_instruction(right_boolean, right_position);
+            self.emit_instruction(left_boolean, left_position);
+        } else {
             self.emit_instruction(
                 Instruction::load_boolean(self.current_register, true, true),
                 operator_position,
@@ -538,13 +580,6 @@ impl<'src> Parser<'src> {
                 Instruction::load_boolean(self.current_register, false, false),
                 operator_position,
             );
-
-        if push_back_left {
-            self.emit_instruction(left_instruction, left_position);
-        }
-
-        if push_back_right {
-            self.emit_instruction(right_instruction, right_position);
         }
 
         Ok(())

dust-lang/src/parser/tests.rs

@@ -2,6 +2,37 @@ use crate::Local;
 
 use super::*;
 
+#[test]
+fn equality_chain() {
+    let source = "1 == 2 == 3;";
+
+    assert_eq!(
+        parse(source),
+        Ok(Chunk::with_data(
+            vec![
+                (
+                    *Instruction::equal(true, 0, 1)
+                        .set_first_argument_to_constant()
+                        .set_second_argument_to_constant(),
+                    Span(2, 4)
+                ),
+                (Instruction::jump(1, true), Span(2, 4)),
+                (
+                    *Instruction::equal(true, 1, 2)
+                        .set_first_argument_to_constant()
+                        .set_second_argument_to_constant(),
+                    Span(7, 9)
+                ),
+                (Instruction::jump(1, true), Span(7, 9)),
+                (Instruction::load_boolean(0, true, true), Span(2, 4)),
+                (Instruction::load_boolean(0, false, false), Span(2, 4)),
+            ],
+            vec![Value::integer(1), Value::integer(2), Value::integer(3)],
+            vec![]
+        )),
+    );
+}
+
 #[test]
 fn not() {
     let source = "!true";

dust-lang/src/vm.rs

@@ -42,7 +42,7 @@ impl Vm {
             vm: &mut Vm,
             instruction: Instruction,
             position: Span,
-        ) -> Result<(Value, Value), VmError> {
+        ) -> Result<(Value, &Value), VmError> {
             let left = if instruction.first_argument_is_constant() {
                 vm.chunk
                     .take_constant(instruction.first_argument(), position)?
@@ -51,9 +51,9 @@ impl Vm {
             };
             let right = if instruction.second_argument_is_constant() {
                 vm.chunk
-                    .take_constant(instruction.second_argument(), position)?
+                    .get_constant(instruction.second_argument(), position)?
             } else {
-                vm.clone(instruction.second_argument(), position)?
+                vm.get(instruction.second_argument(), position)?
             };
 
             Ok((left, right))
@@ -151,7 +151,7 @@ impl Vm {
                 Operation::Add => {
                     let (left, right) = take_constants_or_clone(self, instruction, position)?;
                     let sum = left
-                        .add(&right)
+                        .add(right)
                         .map_err(|error| VmError::Value { error, position })?;
 
                     self.insert(sum, instruction.destination(), position)?;
@@ -159,7 +159,7 @@ impl Vm {
                 Operation::Subtract => {
                     let (left, right) = take_constants_or_clone(self, instruction, position)?;
                     let difference = left
-                        .subtract(&right)
+                        .subtract(right)
                         .map_err(|error| VmError::Value { error, position })?;
 
                     self.insert(difference, instruction.destination(), position)?;
@@ -167,7 +167,7 @@ impl Vm {
                 Operation::Multiply => {
                     let (left, right) = take_constants_or_clone(self, instruction, position)?;
                     let product = left
-                        .multiply(&right)
+                        .multiply(right)
                         .map_err(|error| VmError::Value { error, position })?;
 
                     self.insert(product, instruction.destination(), position)?;
@@ -175,7 +175,7 @@ impl Vm {
                 Operation::Divide => {
                     let (left, right) = take_constants_or_clone(self, instruction, position)?;
                     let quotient = left
-                        .divide(&right)
+                        .divide(right)
                         .map_err(|error| VmError::Value { error, position })?;
 
                     self.insert(quotient, instruction.destination(), position)?;
@@ -183,7 +183,7 @@ impl Vm {
                 Operation::Modulo => {
                     let (left, right) = take_constants_or_clone(self, instruction, position)?;
                     let remainder = left
-                        .modulo(&right)
+                        .modulo(right)
                         .map_err(|error| VmError::Value { error, position })?;
 
                     self.insert(remainder, instruction.destination(), position)?;
@@ -220,7 +220,7 @@ impl Vm {
                 Operation::Equal => {
                     let (left, right) = take_constants_or_clone(self, instruction, position)?;
                     let equal = left
-                        .equal(&right)
+                        .equal(right)
                         .map_err(|error| VmError::Value { error, position })?;
                     let compare_to = instruction.destination_as_boolean();
 
@@ -233,7 +233,7 @@ impl Vm {
                 Operation::Less => {
                     let (left, right) = take_constants_or_clone(self, instruction, position)?;
                     let less = left
-                        .less_than(&right)
+                        .less_than(right)
                         .map_err(|error| VmError::Value { error, position })?;
                     let compare_to = instruction.destination() != 0;
 
@@ -246,7 +246,7 @@ impl Vm {
                 Operation::LessEqual => {
                     let (left, right) = take_constants_or_clone(self, instruction, position)?;
                     let less_equal = left
-                        .less_than_or_equal(&right)
+                        .less_than_or_equal(right)
                         .map_err(|error| VmError::Value { error, position })?;
                     let compare_to = instruction.destination() != 0;
 
@@ -342,6 +342,20 @@ impl Vm {
         }
     }
 
+    fn get(&self, index: u8, position: Span) -> Result<&Value, VmError> {
+        let index = index as usize;
+
+        if let Some(register) = self.register_stack.get(index) {
+            let value = register
+                .as_ref()
+                .ok_or_else(|| VmError::EmptyRegister { index, position })?;
+
+            Ok(value)
+        } else {
+            Err(VmError::RegisterIndexOutOfBounds { position })
+        }
+    }
+
     fn clone(&mut self, index: u8, position: Span) -> Result<Value, VmError> {
         let index = index as usize;