using KumiScript.Interpreter;

namespace KumiScript.Reader
{
    public class SymbolTable
    {
        static SymbolTable? _instance;
        readonly Dictionary<string, Symbol> _table;

        private SymbolTable()
        {
            _instance = this;
            _table = new Dictionary<string, Symbol>();
        }

        public static SymbolTable GetInstance()
        {
            if (_instance is null)
                return new SymbolTable();

            return _instance;
        }

        public Symbol FromString(string s)
        {
            Symbol? sym;
            _table.TryGetValue(s, out sym);
            if (sym is null)
            {
                sym = new Symbol(s);
                _table.Add(s, sym);
            }
            return sym;
        }
    }
}