diff options
| -rw-r--r-- | users/tazjin/rlox/src/interpreter.rs | 73 | ||||
| -rw-r--r-- | users/tazjin/rlox/src/interpreter/tests.rs | 25 | ||||
| -rw-r--r-- | users/tazjin/rlox/src/main.rs | 9 |
3 files changed, 59 insertions, 48 deletions
diff --git a/users/tazjin/rlox/src/interpreter.rs b/users/tazjin/rlox/src/interpreter.rs index 6aab389369ea..bd907542fb5e 100644 --- a/users/tazjin/rlox/src/interpreter.rs +++ b/users/tazjin/rlox/src/interpreter.rs @@ -16,32 +16,35 @@ mod tests; // Representation of all callables, including builtins & user-defined // functions. #[derive(Clone, Debug)] -pub enum Callable { +pub enum Callable<'a> { Builtin(&'static dyn builtins::Builtin), + Function(Rc<parser::Function<'a>>), } -impl Callable { +impl<'a> Callable<'a> { fn arity(&self) -> usize { match self { Callable::Builtin(builtin) => builtin.arity(), + _ => unimplemented!(), } } - fn call(&self, args: Vec<Value>) -> Result<Value, Error> { + fn call(&self, args: Vec<Value>) -> Result<Value<'a>, Error> { match self { Callable::Builtin(builtin) => builtin.call(args), + _ => unimplemented!(), } } } // Representation of an in-language value. #[derive(Clone, Debug)] -pub enum Value { +pub enum Value<'a> { Literal(Literal), - Callable(Callable), + Callable(Callable<'a>), } -impl PartialEq for Value { +impl<'a> PartialEq for Value<'a> { fn eq(&self, other: &Self) -> bool { match (self, other) { (Value::Literal(lhs), Value::Literal(rhs)) => lhs == rhs, @@ -51,13 +54,13 @@ impl PartialEq for Value { } } -impl From<Literal> for Value { - fn from(lit: Literal) -> Value { +impl<'a> From<Literal> for Value<'a> { + fn from(lit: Literal) -> Value<'a> { Value::Literal(lit) } } -impl Value { +impl<'a> Value<'a> { fn expect_literal(self) -> Result<Literal, Error> { match self { Value::Literal(lit) => Ok(lit), @@ -67,19 +70,19 @@ impl Value { } #[derive(Debug, Default)] -struct Environment { - enclosing: Option<Rc<RwLock<Environment>>>, - values: HashMap<String, Value>, +struct Environment<'a> { + enclosing: Option<Rc<RwLock<Environment<'a>>>>, + values: HashMap<String, Value<'a>>, } -impl Environment { - fn define(&mut self, name: &scanner::Token, value: Value) -> Result<(), Error> { +impl<'a> Environment<'a> { + fn define(&mut self, name: &scanner::Token, value: Value<'a>) -> Result<(), Error> { let ident = identifier_str(name)?; self.values.insert(ident.into(), value); Ok(()) } - fn get(&self, name: &parser::Variable) -> Result<Value, Error> { + fn get(&self, name: &parser::Variable) -> Result<Value<'a>, Error> { let ident = identifier_str(&name.0)?; self.values @@ -98,7 +101,7 @@ impl Environment { }) } - fn assign(&mut self, name: &scanner::Token, value: Value) -> Result<(), Error> { + fn assign(&mut self, name: &scanner::Token, value: Value<'a>) -> Result<(), Error> { let ident = identifier_str(name)?; match self.values.get_mut(ident) { @@ -132,11 +135,11 @@ fn identifier_str<'a>(name: &'a scanner::Token) -> Result<&'a str, Error> { } #[derive(Debug)] -pub struct Interpreter { - env: Rc<RwLock<Environment>>, +pub struct Interpreter<'a> { + env: Rc<RwLock<Environment<'a>>>, } -impl Interpreter { +impl<'a> Interpreter<'a> { /// Create a new interpreter and configure the initial global /// variable set. pub fn create() -> Self { @@ -156,28 +159,28 @@ impl Interpreter { } // Environment modification helpers - fn define_var(&mut self, name: &scanner::Token, value: Value) -> Result<(), Error> { + fn define_var(&mut self, name: &scanner::Token, value: Value<'a>) -> Result<(), Error> { self.env .write() .expect("environment lock is poisoned") .define(name, value) } - fn assign_var(&mut self, name: &scanner::Token, value: Value) -> Result<(), Error> { + fn assign_var(&mut self, name: &scanner::Token, value: Value<'a>) -> Result<(), Error> { self.env .write() .expect("environment lock is poisoned") .assign(name, value) } - fn get_var(&mut self, var: &parser::Variable) -> Result<Value, Error> { + fn get_var(&mut self, var: &parser::Variable) -> Result<Value<'a>, Error> { self.env .read() .expect("environment lock is poisoned") .get(var) } - fn set_enclosing(&mut self, parent: Rc<RwLock<Environment>>) { + fn set_enclosing(&mut self, parent: Rc<RwLock<Environment<'a>>>) { self.env .write() .expect("environment lock is poisoned") @@ -185,7 +188,7 @@ impl Interpreter { } // Interpreter itself - pub fn interpret<'a>(&mut self, program: &Block<'a>) -> Result<Value, Error> { + pub fn interpret(&mut self, program: &Block<'a>) -> Result<Value<'a>, Error> { let mut value = Value::Literal(Literal::Nil); for stmt in program { @@ -195,7 +198,7 @@ impl Interpreter { Ok(value) } - fn interpret_stmt<'a>(&mut self, stmt: &Statement<'a>) -> Result<Value, Error> { + fn interpret_stmt(&mut self, stmt: &Statement<'a>) -> Result<Value<'a>, Error> { let value = match stmt { Statement::Expr(expr) => self.eval(expr)?, Statement::Print(expr) => { @@ -214,7 +217,7 @@ impl Interpreter { Ok(value) } - fn interpret_var<'a>(&mut self, var: &parser::Var<'a>) -> Result<Value, Error> { + fn interpret_var(&mut self, var: &parser::Var<'a>) -> Result<Value<'a>, Error> { let init = var.initialiser.as_ref().ok_or_else(|| Error { line: var.name.line, kind: ErrorKind::InternalError("missing variable initialiser".into()), @@ -224,7 +227,7 @@ impl Interpreter { Ok(value) } - fn interpret_block<'a>(&mut self, block: &parser::Block<'a>) -> Result<Value, Error> { + fn interpret_block(&mut self, block: &parser::Block<'a>) -> Result<Value<'a>, Error> { // Initialise a new environment and point it at the parent // (this is a bit tedious because we need to wrap it in and // out of the Rc). @@ -241,7 +244,7 @@ impl Interpreter { return result; } - fn interpret_if<'a>(&mut self, if_stmt: &parser::If<'a>) -> Result<Value, Error> { + fn interpret_if(&mut self, if_stmt: &parser::If<'a>) -> Result<Value<'a>, Error> { let condition = self.eval(&if_stmt.condition)?; if eval_truthy(&condition) { @@ -253,7 +256,7 @@ impl Interpreter { } } - fn interpret_while<'a>(&mut self, stmt: &parser::While<'a>) -> Result<Value, Error> { + fn interpret_while(&mut self, stmt: &parser::While<'a>) -> Result<Value<'a>, Error> { let mut value = Value::Literal(Literal::Nil); while eval_truthy(&self.eval(&stmt.condition)?) { value = self.interpret_stmt(&stmt.body)?; @@ -262,7 +265,7 @@ impl Interpreter { Ok(value) } - fn eval<'a>(&mut self, expr: &Expr<'a>) -> Result<Value, Error> { + fn eval(&mut self, expr: &Expr<'a>) -> Result<Value<'a>, Error> { match expr { Expr::Assign(assign) => self.eval_assign(assign), Expr::Literal(lit) => Ok(lit.clone().into()), @@ -275,7 +278,7 @@ impl Interpreter { } } - fn eval_unary<'a>(&mut self, expr: &parser::Unary<'a>) -> Result<Value, Error> { + fn eval_unary(&mut self, expr: &parser::Unary<'a>) -> Result<Value<'a>, Error> { let right = self.eval(&*expr.right)?; match (&expr.operator.kind, right) { @@ -294,7 +297,7 @@ impl Interpreter { } } - fn eval_binary<'a>(&mut self, expr: &parser::Binary<'a>) -> Result<Value, Error> { + fn eval_binary(&mut self, expr: &parser::Binary<'a>) -> Result<Value<'a>, Error> { let left = self.eval(&*expr.left)?.expect_literal()?; let right = self.eval(&*expr.right)?.expect_literal()?; @@ -338,13 +341,13 @@ impl Interpreter { Ok(result.into()) } - fn eval_assign<'a>(&mut self, assign: &parser::Assign<'a>) -> Result<Value, Error> { + fn eval_assign(&mut self, assign: &parser::Assign<'a>) -> Result<Value<'a>, Error> { let value = self.eval(&assign.value)?; self.assign_var(&assign.name, value.clone())?; Ok(value) } - fn eval_logical<'a>(&mut self, logical: &parser::Logical<'a>) -> Result<Value, Error> { + fn eval_logical(&mut self, logical: &parser::Logical<'a>) -> Result<Value<'a>, Error> { let left = eval_truthy(&self.eval(&logical.left)?); let right = eval_truthy(&self.eval(&logical.right)?); @@ -358,7 +361,7 @@ impl Interpreter { } } - fn eval_call<'a>(&mut self, call: &parser::Call<'a>) -> Result<Value, Error> { + fn eval_call(&mut self, call: &parser::Call<'a>) -> Result<Value<'a>, Error> { let callable = match self.eval(&call.callee)? { Value::Callable(c) => c, Value::Literal(v) => { diff --git a/users/tazjin/rlox/src/interpreter/tests.rs b/users/tazjin/rlox/src/interpreter/tests.rs index 3aaea707d64b..93a025c5e832 100644 --- a/users/tazjin/rlox/src/interpreter/tests.rs +++ b/users/tazjin/rlox/src/interpreter/tests.rs @@ -1,8 +1,11 @@ use super::*; +fn code(code: &str) -> Vec<char> { + code.chars().collect() +} + /// Evaluate a code snippet, returning a value. -fn parse_eval(code: &str) -> Value { - let chars: Vec<char> = code.chars().collect(); +fn parse_eval<'a>(chars: &'a [char]) -> Value<'a> { let tokens = scanner::scan(&chars).expect("could not scan code"); let program = parser::parse(tokens).expect("could not parse code"); Interpreter::create() @@ -12,7 +15,7 @@ fn parse_eval(code: &str) -> Value { #[test] fn test_if() { - let result = parse_eval( + let code = code( r#" if (42 > 23) "pass"; @@ -21,12 +24,15 @@ else "#, ); - assert_eq!(Value::Literal(Literal::String("pass".into())), result); + assert_eq!( + Value::Literal(Literal::String("pass".into())), + parse_eval(&code) + ); } #[test] fn test_scope() { - let result = parse_eval( + let code = code( r#" var result = ""; @@ -48,16 +54,19 @@ var c = "global c"; assert_eq!( Value::Literal(Literal::String("inner a, outer b, global c".into())), - result + parse_eval(&code), ); } #[test] fn test_binary_operators() { - assert_eq!(Value::Literal(Literal::Number(42.0)), parse_eval("40 + 2;")); + assert_eq!( + Value::Literal(Literal::Number(42.0)), + parse_eval(&code("40 + 2;")) + ); assert_eq!( Value::Literal(Literal::String("foobar".into())), - parse_eval("\"foo\" + \"bar\";") + parse_eval(&code("\"foo\" + \"bar\";")) ); } diff --git a/users/tazjin/rlox/src/main.rs b/users/tazjin/rlox/src/main.rs index 8970349bfa69..222eb4cd534f 100644 --- a/users/tazjin/rlox/src/main.rs +++ b/users/tazjin/rlox/src/main.rs @@ -25,14 +25,12 @@ fn main() { // Run Lox code from a file and print results to stdout fn run_file(file: &str) { let contents = fs::read_to_string(file).expect("failed to read the input file"); - let mut lox = interpreter::Interpreter::create(); - run(&mut lox, &contents); + run(&contents); } // Evaluate Lox code interactively in a shitty REPL. fn run_prompt() { let mut line = String::new(); - let mut lox = interpreter::Interpreter::create(); loop { print!("> "); @@ -40,13 +38,14 @@ fn run_prompt() { io::stdin() .read_line(&mut line) .expect("failed to read user input"); - run(&mut lox, &line); + run(&line); line.clear(); } } -fn run(lox: &mut interpreter::Interpreter, code: &str) { +fn run(code: &str) { let chars: Vec<char> = code.chars().collect(); + let mut lox = interpreter::Interpreter::create(); match scanner::scan(&chars) { Ok(tokens) => match parser::parse(tokens) { |