Add basic VM

dust-lang/src/instruction.rs

@@ -0,0 +1,23 @@
+use crate::{Identifier, Span, Value};
+
+#[derive(Debug, PartialEq, Clone)]
+pub struct Instruction {
+    pub operation: Operation,
+    pub span: Span,
+}
+
+impl Instruction {
+    pub fn new(operation: Operation, span: Span) -> Self {
+        Self { operation, span }
+    }
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum Operation {
+    Add(Box<(Instruction, Instruction)>),
+    Assign(Box<(Instruction, Instruction)>),
+    Constant(Value),
+    Identifier(Identifier),
+    List(Vec<Instruction>),
+    Multiply(Box<(Instruction, Instruction)>),
+}

dust-lang/src/lib.rs

@@ -8,15 +8,21 @@ interpret Dust code. The `interpret` function is a convenience function that cre
 `Interpreter` and runs the given source code.
 */
 pub mod identifier;
+pub mod instruction;
 pub mod lex;
 pub mod parse;
 pub mod token;
 pub mod r#type;
 pub mod value;
+pub mod vm;
 
 pub use identifier::Identifier;
+pub use instruction::{Instruction, Operation};
+pub use lex::{lex, LexError, Lexer};
+pub use parse::{parse, ParseError, Parser};
 pub use r#type::Type;
 pub use token::Token;
-pub use value::Value;
+pub use value::{Value, ValueError};
+pub use vm::Vm;
 
 pub type Span = (usize, usize);

dust-lang/src/parse.rs

@@ -1,36 +1,24 @@
 use crate::{
-    identifier::Identifier,
     lex::{LexError, Lexer},
-    Span, Token, Value,
+    Instruction, Operation, Span, Token, Value,
 };
 
-pub fn parse(input: &str) -> Result<Instruction, ParseError> {
+pub fn parse(input: &str) -> Result<Vec<Instruction>, ParseError> {
     let lexer = Lexer::new(input);
     let mut parser = Parser::new(lexer);
+    let mut instructions = Vec::new();
 
-    parser.parse()
-}
+    loop {
+        let instruction = parser.parse()?;
 
-#[derive(Debug, PartialEq, Clone)]
-pub struct Instruction {
-    pub operation: Operation,
-    pub span: Span,
-}
+        instructions.push(instruction);
 
-impl Instruction {
-    pub fn new(operation: Operation, span: Span) -> Self {
-        Self { operation, span }
+        if let Token::Eof = parser.current.0 {
+            break;
+        }
     }
-}
 
-#[derive(Debug, PartialEq, Clone)]
-pub enum Operation {
-    Add(Box<(Instruction, Instruction)>),
-    Assign(Box<(Instruction, Instruction)>),
-    Constant(Value),
-    Identifier(Identifier),
-    List(Vec<Instruction>),
-    Multiply(Box<(Instruction, Instruction)>),
+    Ok(instructions)
 }
 
 pub struct Parser<'src> {
@@ -205,6 +193,7 @@ impl From<LexError> for ParseError {
 
 #[cfg(test)]
 mod tests {
+    use crate::Identifier;
 
     use super::*;
 
@@ -214,7 +203,7 @@ mod tests {
 
         assert_eq!(
             parse(input),
-            Ok(Instruction::new(
+            Ok(vec![Instruction::new(
                 Operation::List(vec![
                     Instruction::new(Operation::Constant(Value::integer(1)), (1, 2)),
                     Instruction::new(
@@ -245,7 +234,7 @@ mod tests {
                     )
                 ]),
                 (0, 24)
-            ))
+            )])
         );
     }
 
@@ -255,13 +244,13 @@ mod tests {
 
         assert_eq!(
             parse(input),
-            Ok(Instruction::new(
+            Ok(vec![Instruction::new(
                 Operation::List(vec![
                     Instruction::new(Operation::Constant(Value::integer(1)), (1, 2)),
                     Instruction::new(Operation::Constant(Value::integer(2)), (4, 5)),
                 ]),
                 (0, 6)
-            ))
+            )])
         );
     }
 
@@ -271,7 +260,7 @@ mod tests {
 
         assert_eq!(
             parse(input),
-            Ok(Instruction::new(Operation::List(vec![]), (0, 2)))
+            Ok(vec![Instruction::new(Operation::List(vec![]), (0, 2))])
         );
     }
 
@@ -281,10 +270,10 @@ mod tests {
 
         assert_eq!(
             parse(input),
-            Ok(Instruction::new(
+            Ok(vec![Instruction::new(
                 Operation::Constant(Value::float(42.0)),
                 (0, 4)
-            ))
+            )])
         );
     }
 
@@ -294,13 +283,13 @@ mod tests {
 
         assert_eq!(
             parse(input),
-            Ok(Instruction::new(
+            Ok(vec![Instruction::new(
                 Operation::Add(Box::new((
                     Instruction::new(Operation::Constant(Value::integer(1)), (0, 1)),
                     Instruction::new(Operation::Constant(Value::integer(2)), (4, 5)),
                 ))),
                 (0, 5)
-            ))
+            )])
         );
     }
 
@@ -310,13 +299,13 @@ mod tests {
 
         assert_eq!(
             parse(input),
-            Ok(Instruction::new(
+            Ok(vec![Instruction::new(
                 Operation::Multiply(Box::new((
                     Instruction::new(Operation::Constant(Value::integer(1)), (0, 1)),
                     Instruction::new(Operation::Constant(Value::integer(2)), (4, 5)),
                 ))),
                 (0, 5)
-            ))
+            )])
         );
     }
 
@@ -326,7 +315,7 @@ mod tests {
 
         assert_eq!(
             parse(input),
-            Ok(Instruction::new(
+            Ok(vec![Instruction::new(
                 Operation::Add(Box::new((
                     Instruction::new(Operation::Constant(Value::integer(1)), (0, 1)),
                     Instruction::new(
@@ -338,7 +327,7 @@ mod tests {
                     ),
                 ))),
                 (0, 9)
-            ))
+            )])
         );
     }
 
@@ -348,7 +337,7 @@ mod tests {
 
         assert_eq!(
             parse(input),
-            Ok(Instruction::new(
+            Ok(vec![Instruction::new(
                 Operation::Assign(Box::new((
                     Instruction::new(Operation::Identifier(Identifier::new("a")), (0, 1)),
                     Instruction::new(
@@ -372,7 +361,7 @@ mod tests {
                     ),
                 ))),
                 (0, 13)
-            ))
+            )])
         );
     }
 }

dust-lang/src/value.rs

@@ -78,6 +78,16 @@ impl Value {
             None
         }
     }
+
+    pub fn add(&self, other: &Value) -> Result<Value, ValueError> {
+        match (self.inner().as_ref(), other.inner().as_ref()) {
+            (ValueInner::Float(left), ValueInner::Float(right)) => Ok(Value::float(left + right)),
+            (ValueInner::Integer(left), ValueInner::Integer(right)) => {
+                Ok(Value::integer(left + right))
+            }
+            _ => Err(ValueError::CannotAdd(self.clone(), other.clone())),
+        }
+    }
 }
 
 impl Display for Value {
@@ -502,3 +512,8 @@ impl Ord for ValueInner {
         }
     }
 }
+
+#[derive(Clone, Debug, PartialEq)]
+pub enum ValueError {
+    CannotAdd(Value, Value),
+}

dust-lang/src/vm.rs

@@ -0,0 +1,85 @@
+use crate::{parse, Instruction, Operation, ParseError, Parser, Value, ValueError};
+
+pub fn run(input: &str) -> Result<Option<Value>, VmError> {
+    let instructions = parse(input)?;
+    let vm = Vm::new(instructions);
+
+    vm.run()
+}
+
+pub struct Vm {
+    instructions: Vec<Instruction>,
+}
+
+impl Vm {
+    pub fn new(instructions: Vec<Instruction>) -> Self {
+        Vm { instructions }
+    }
+
+    pub fn run(&self) -> Result<Option<Value>, VmError> {
+        let mut previous_value = None;
+
+        for instruction in &self.instructions {
+            previous_value = self.run_instruction(instruction)?;
+        }
+
+        Ok(previous_value)
+    }
+
+    fn run_instruction(&self, instruction: &Instruction) -> Result<Option<Value>, VmError> {
+        match &instruction.operation {
+            Operation::Add(instructions) => {
+                let left = if let Some(value) = self.run_instruction(&instructions.0)? {
+                    value
+                } else {
+                    return Err(VmError::ExpectedValue(instructions.0.operation.clone()));
+                };
+                let right = if let Some(value) = self.run_instruction(&instructions.1)? {
+                    value
+                } else {
+                    return Err(VmError::ExpectedValue(instructions.1.operation.clone()));
+                };
+                let sum = left.add(&right)?;
+
+                Ok(Some(sum))
+            }
+            Operation::Assign(_) => todo!(),
+            Operation::Constant(value) => Ok(Some(value.clone())),
+            Operation::Identifier(_) => todo!(),
+            Operation::List(_) => todo!(),
+            Operation::Multiply(_) => todo!(),
+        }
+    }
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub enum VmError {
+    ExpectedValue(Operation),
+    InvalidOperation(Operation),
+    ParseError(ParseError),
+    ValueError(ValueError),
+}
+
+impl From<ParseError> for VmError {
+    fn from(v: ParseError) -> Self {
+        Self::ParseError(v)
+    }
+}
+
+impl From<ValueError> for VmError {
+    fn from(v: ValueError) -> Self {
+        Self::ValueError(v)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn add() {
+        let input = "1 + 2";
+
+        assert_eq!(run(input), Ok(Some(Value::integer(3))));
+    }
+}