KumiScript/reader/AtomToken.cs

using KumiScript.Interpreter;

namespace KumiScript.Reader
{
    public class AtomToken : Token
    {
        readonly string _value;
        public AtomToken(string value)
        {
            _value = value;
        }

        public override Expression Accept(ITokenVisitor tokenVisitor)
        {
            return tokenVisitor.VisitAtom(this);
        }

        public virtual Expression ToExpression()
        {
            decimal f;
            if (decimal.TryParse(_value, out f))
                return new NumberExpression(f);
            
            if (_value == "null")
                return NilExpression.GetInstance();
            
            if (_value == "t")
                return TrueExpression.GetInstance();
            
            return new SymbolExpression(SymbolTable.GetInstance().FromString(_value));
        }

        public override string GetValue()
        {
            return _value;
        }
    }
}