public object EvaluateExpr(Ast.Expr expr, ScriptEnv env)
{
var dt = _notebook.Query($"SELECT ({expr.Sql})", env.Vars);
if (dt.Columns.Count == 1 && dt.Rows.Count == 1)
{
return(dt.Rows[0][0]);
}
else
{
throw new ScriptException(
$"Evaluation of expression \"{expr.Sql}\" did not produce a value.");
}
}
public T EvaluateExpr <T>(Ast.Expr expr, ScriptEnv env)
{
var value = EvaluateExpr(expr, env);
if (typeof(T).IsAssignableFrom(value.GetType()))
{
return((T)value);
}
else
{
throw new ScriptException(
$"Evaluation of expression \"{expr.Sql}\" produced a value of type " +
$"\"{value.GetType().Name}\" instead of the expected \"{typeof(T).Name}\".");
}
}
