public override async Task<object> Invoke(IExpression head, IExpression[] args)
{
var target = await head.Eval(this);
var macro = target as PlasticMacro;
var expression = target as IExpression;
var array = target as object[];
if (macro != null)
{
return await InvokeMacro(this, macro, args);
}
if (expression != null)
{
return await expression.Eval(this);
}
if (array != null)
{
var index = (int)(decimal) await args.First().Eval(this);
return array[index];
}
throw new NotImplementedException();
}
