Upsilon/Upsilon/Binder/BoundScope.cs

using System;
using System.Collections.Generic;
using Upsilon.Binder.VariableSymbols;
using Type = Upsilon.BaseTypes.Type;

namespace Upsilon.Binder
{
    public class BoundScope : IDisposable
    {
        public readonly BoundScope ParentScope;
        public BoundScope ReadOnlyScope { get; private set; }
        public readonly Dictionary<string, VariableSymbol> Variables;
        public Type ReturnType { get; set; } = Type.Nil;

        public BoundScope(BoundScope parentScope)
        {
            ParentScope = parentScope;
            Variables   = new Dictionary<string, VariableSymbol>();
        }
        public BoundScope(Dictionary<string, VariableSymbol> variables, BoundScope parentScope)
        {
            ParentScope = parentScope;
            Variables = variables;
        }

        public static BoundScope WithReadOnlyScope(BoundScope readOnlyScope)
        {
            var scope = new BoundScope(null) {ReadOnlyScope = readOnlyScope};
            return scope;
        }

        public void Dispose()
        {
            //Variables.Clear();
        }

        public void DefineLocalVariable(VariableSymbol var)
        {
            Variables.Add(var.Name, var);
        }

        public void AssignToNearest(VariableSymbol var)
        {
            if (Variables.ContainsKey(var.Name))
            {

            }
            else if (ParentScope != null)
            {
                ParentScope.AssignToNearest(var);
            }
            else
            {
                Variables.Add(var.Name, var);
            }
        }

        public bool TryGetVariable(string key, bool allowUpperScopes, out VariableSymbol result)
        {
            if (Variables.TryGetValue(key, out result))
            {
                return true;
            }
            if (ParentScope != null && allowUpperScopes)
            {
                return ParentScope.TryGetVariable(key, true, out result);
            }
            if (ReadOnlyScope != null && allowUpperScopes)
            {
                return ReadOnlyScope.TryGetVariable(key, true, out result);
            }
            return false;
        }

    }
}