private (RacketExpression?, string) ParseLine(string str)
{
RacketExpression?expression = null;
RacketValueType? retValue;
string retValueString;
try
{
expression = RacketExpression.Parse(str);
retValue = expression?.Evaluate();
retValueString = retValue?.ToString() ?? "";
}
catch (Exception ex)
{
retValueString = $"; {ex.Message}";
}
if (!string.IsNullOrEmpty(retValueString))
{
retValueString += Environment.NewLine;
}
return(expression, retValueString);
}
