diff --git a/schala-lang/src/eval.rs b/schala-lang/src/eval.rs index d6f2b00..bef1051 100644 --- a/schala-lang/src/eval.rs +++ b/schala-lang/src/eval.rs @@ -44,246 +44,6 @@ enum ValueEntry { type EvalResult = Result; - -/* -#[derive(Debug, PartialEq, Clone)] -enum FullyEvaluatedExpr { - UnsignedInt(u64), - SignedInt(i64), - Float(f64), - Str(String), - Bool(bool), - FuncLit(Rc), - Custom { - string_rep: Rc, - }, - Tuple(Vec), - List(Vec) -} - -impl FullyEvaluatedExpr { - fn to_string(&self) -> String { - use self::FullyEvaluatedExpr::*; - match self { - &UnsignedInt(ref n) => format!("{}", n), - &SignedInt(ref n) => format!("{}", n), - &Float(ref f) => format!("{}", f), - &Str(ref s) => format!("\"{}\"", s), - &Bool(ref b) => format!("{}", b), - &Custom { ref string_rep } => format!("{}", string_rep), - &Tuple(ref items) => { - let mut buf = String::new(); - write!(buf, "(").unwrap(); - for term in items.iter().map(|e| Some(e)).intersperse(None) { - match term { - Some(e) => write!(buf, "{}", e.to_string()).unwrap(), - None => write!(buf, ", ").unwrap(), - }; - } - write!(buf, ")").unwrap(); - buf - }, - &FuncLit(ref name) => format!("", name), - &List(ref items) => { - let mut buf = String::new(); - write!(buf, "[").unwrap(); - for term in items.iter().map(|e| Some(e)).intersperse(None) { - match term { - Some(e) => write!(buf, "{}", e.to_string()).unwrap(), - None => write!(buf, ", ").unwrap() - } - } - write!(buf, "]").unwrap(); - buf - } - } - } -} -*/ - - /* - - pub fn new_with_parent(parent: &'a State<'a>) -> State<'a> { - State { parent_frame: Some(parent), values: HashMap::new() } - } - - pub fn evaluate(&mut self, ast: AST) -> Vec> { - let mut acc = vec![]; - for statement in ast.0 { - match self.eval_statement(statement) { - Ok(output) => { - if let Some(fully_evaluated) = output { - acc.push(Ok(fully_evaluated.to_string())); - } - }, - Err(error) => { - acc.push(Err(format!("Eval error: {}", error))); - return acc; - }, - } - } - acc - } -} - -impl<'a> State<'a> { - fn eval_statement(&mut self, statement: Statement) -> EvalResult> { - Ok(match statement { - Statement::ExpressionStatement(expr) => Some(self.eval_expr(expr)?), - Statement::Declaration(decl) => { self.eval_decl(decl)?; None } - }) - } - - fn eval_decl(&mut self, decl: Declaration) -> EvalResult<()> { - use self::Declaration::*; - use self::Variant::*; - - match decl { - FuncDecl(signature, statements) => { - let name = signature.name; - let param_names: Vec> = signature.params.iter().map(|fp| fp.0.clone()).collect(); - self.insert(name, ValueEntry::Function { body: statements.clone(), param_names }); - }, - TypeDecl(_name, body) => { - for variant in body.0.iter() { - match variant { - &UnitStruct(ref name) => self.insert(name.clone(), - ValueEntry::Binding { val: FullyEvaluatedExpr::Custom { string_rep: name.clone() } }), - &TupleStruct(ref _name, ref _args) => unimplemented!(), - &Record(ref _name, ref _fields) => unimplemented!(), - }; - } - }, - Binding { name, expr, ..} => { - let val = self.eval_expr(expr)?; - self.insert(name.clone(), ValueEntry::Binding { val }); - }, - _ => return Err(format!("Declaration evaluation not yet implemented")) - } - Ok(()) - } - - fn eval_expr(&mut self, expr: Expression) -> EvalResult { - use self::ExpressionType::*; - use self::FullyEvaluatedExpr::*; - - let expr_type = expr.0; - match expr_type { - IntLiteral(n) => Ok(UnsignedInt(n)), - FloatLiteral(f) => Ok(Float(f)), - StringLiteral(s) => Ok(Str(s.to_string())), - BoolLiteral(b) => Ok(Bool(b)), - PrefixExp(op, expr) => self.eval_prefix_exp(op, expr), - BinExp(op, lhs, rhs) => self.eval_binexp(op, lhs, rhs), - Value(name) => self.eval_value(name), - TupleLiteral(expressions) => { - let mut evals = Vec::new(); - for expr in expressions { - match self.eval_expr(expr) { - Ok(fully_evaluated) => evals.push(fully_evaluated), - error => return error, - } - } - Ok(Tuple(evals)) - } - Call { f, arguments } => { - let mut evaled_arguments = Vec::new(); - for arg in arguments.into_iter() { - evaled_arguments.push(self.eval_expr(arg)?); - } - self.eval_application(*f, evaled_arguments) - }, - Index { box indexee, indexers } => { - let evaled = self.eval_expr(indexee)?; - match evaled { - Tuple(mut exprs) => { - let len = indexers.len(); - if len == 1 { - let idx = indexers.into_iter().nth(0).unwrap(); - match self.eval_expr(idx)? { - UnsignedInt(n) if (n as usize) < exprs.len() => Ok(exprs.drain(n as usize..).next().unwrap()), - UnsignedInt(n) => Err(format!("Index {} out of range", n)), - other => Err(format!("{:?} is not an unsigned integer", other)), - } - } else { - Err(format!("Tuple index must be one integer")) - } - }, - _ => Err(format!("Bad index expression")) - } - }, - ListLiteral(items) => Ok(List(items.into_iter().map(|item| self.eval_expr(item)).collect::,_>>()?)), - x => Err(format!("Unimplemented thing {:?}", x)), - } - } - - fn eval_application(&mut self, f: Expression, arguments: Vec) -> EvalResult { - use self::ExpressionType::*; - match f { - Expression(Value(ref identifier), _) if self.is_builtin(identifier) => self.eval_builtin(identifier, arguments), - Expression(Value(identifier), _) => { - match self.lookup(&identifier) { - Some(&ValueEntry::Function { ref body, ref param_names }) => { - if arguments.len() != param_names.len() { - return Err(format!("Wrong number of arguments for the function")); - } - let mut new_state = State::new_with_parent(self); - let sub_ast = body.clone(); - for (param, val) in param_names.iter().zip(arguments.into_iter()) { - new_state.insert(param.clone(), ValueEntry::Binding { val }); - } - let mut ret: Option = None; - for statement in sub_ast.into_iter() { - ret = new_state.eval_statement(statement)?; - } - Ok(ret.unwrap_or(FullyEvaluatedExpr::Custom { string_rep: Rc::new("()".to_string()) })) - }, - _ => Err(format!("Function {} not found", identifier)), - } - }, - x => Err(format!("Trying to apply {:?} which is not a function", x)), - } - } - fn is_builtin(&self, name: &Rc) -> bool { - match &name.as_ref()[..] { - "print" | "println" => true, - _ => false - } - } - fn eval_builtin(&mut self, name: &Rc, args: Vec) -> EvalResult { - use self::FullyEvaluatedExpr::*; - match &name.as_ref()[..] { - "print" => { - for arg in args { - print!("{}", arg.to_string()); - } - Ok(Tuple(vec![])) - }, - "println" => { - for arg in args { - println!("{}", arg.to_string()); - } - Ok(Tuple(vec![])) - }, - _ => unreachable!() - } - } - fn eval_value(&mut self, name: Rc) -> EvalResult { - use self::ValueEntry::*; - match self.lookup(&name) { - None => return Err(format!("Value {} not found", *name)), - Some(lookup) => match lookup { - &Binding { ref val } => Ok(val.clone()), - &Function { .. } => Ok(FullyEvaluatedExpr::FuncLit(name.clone())) - } - } - } - -} -*/ - -/* BELOW HERE NEW STUFF */ - impl Expr { fn to_repl(&self) -> String { use self::Lit::*;