parrot/evaluator.py

from typing import Dict, List, Optional, cast
from position import Node
from utils import Err, Ok, Result
import parsed

class Value:
    pass

class Unit(Value):
    def __init__(self) -> None:
        super().__init__()

class Int(Value):
    def __init__(self, value: int) -> None:
        super().__init__()
        self.value = value

class Char(Value):
    def __init__(self, value: str) -> None:
        super().__init__()
        self.value = value

class String(Value):
    def __init__(self, value: str) -> None:
        super().__init__()
        self.value = value

class Bool(Value):
    def __init__(self, value: bool) -> None:
        super().__init__()
        self.value = value

class EvalResult:
    pass

class ValueResult(EvalResult):
    def __init__(self, value: Value) -> None:
        super().__init__()
        self.value = value

class ReturnResult(EvalResult):
    def __init__(self, value: Optional[Value]) -> None:
        super().__init__()
        self.value = value

class BreakResult(EvalResult):
    def __init__(self, value: Optional[Value]) -> None:
        super().__init__()
        self.value = value

class ContinueResult(EvalResult):
    def __init__(self, value: Optional[Value]) -> None:
        super().__init__()
        self.value = value

class PanicResult(EvalResult):
    def __init__(self, message: str) -> None:
        super().__init__()
        self.message = message

class SymbolTable:
    def __init__(self) -> None:
        self.symbols: Dict[str, Value] = {}

    def define(self, symbol_id: str, value: Value) -> Result[None, str]:
        if symbol_id in self.symbols:
            return Err("symbol already defined")
        return Ok(None)

class Evaluator:
    def __init__(self) -> None:
        pass

    def evaluate(self, ast: List[Node[parsed.Expr]]) -> None:
        for node in ast:
            self.eval_expr(node)

    def eval_expr(self, node: Node[parsed.Expr]) -> EvalResult:
        if isinstance(node.value, parsed.ExprError):
            return PanicResult(f"error: {cast(parsed.ExprError, node.value).message}, at {node.span}")
        elif isinstance(node.value, parsed.Id):
            raise NotImplementedError()
        elif isinstance(node.value, parsed.Int):
            return ValueResult(Int(cast(parsed.Int, node.value).value))
        elif isinstance(node.value, parsed.Char):
            return ValueResult(Char(cast(parsed.Char, node.value).value))
        elif isinstance(node.value, parsed.String):
            return ValueResult(String(cast(parsed.String, node.value).value))
        elif isinstance(node.value, parsed.Bool):
            return ValueResult(Bool(cast(parsed.Bool, node.value).value))
        elif isinstance(node.value, parsed.Unit):
            return ValueResult(Unit())
        elif isinstance(node.value, parsed.Tuple):
            raise NotImplementedError()
        elif isinstance(node.value, parsed.Block):
            raise NotImplementedError()
        elif isinstance(node.value, parsed.Lambda):
            raise NotImplementedError()
        elif isinstance(node.value, parsed.If):
            raise NotImplementedError()
        elif isinstance(node.value, parsed.Match):
            raise NotImplementedError()
        elif isinstance(node.value, parsed.Loop):
            raise NotImplementedError()
        elif isinstance(node.value, parsed.While):
            raise NotImplementedError()
        elif isinstance(node.value, parsed.For):
            raise NotImplementedError()
        elif isinstance(node.value, parsed.StructMember):
            raise NotImplementedError()
        elif isinstance(node.value, parsed.TupleMember):
            raise NotImplementedError()
        elif isinstance(node.value, parsed.Index):
            raise NotImplementedError()
        elif isinstance(node.value, parsed.Call):
            raise NotImplementedError()
        elif isinstance(node.value, parsed.Unary):
            raise NotImplementedError()
        elif isinstance(node.value, parsed.Binary):
            raise NotImplementedError()
        elif isinstance(node.value, parsed.Assign):
            raise NotImplementedError()
        elif isinstance(node.value, parsed.Let):
            raise NotImplementedError()
        elif isinstance(node.value, parsed.Function):
            raise NotImplementedError()
        elif isinstance(node.value, parsed.Return):
            raise NotImplementedError()
        elif isinstance(node.value, parsed.Break):
            raise NotImplementedError()
        elif isinstance(node.value, parsed.Continue):
            raise NotImplementedError()
        else:
            raise NotImplementedError(str(node))