# Vertically stack parboxes in a cell of a table

I need to insert an enumerate environment in a table.

Following hints from this page: itemize in a tabular environment, I used \parbox to prevent error (https://tex.stackexchange.com/questions/141628/putting-itemize-environment-in-a-tabular-environment).

The issue is that I have two par boxes line up horizontally when I need them vertically stacked. How to stack par boxes in a table?

\documentclass{article}
\usepackage{enumitem}
\usepackage{longtable}
\usepackage{booktabs}

\newcommand{\fuda}[2]{%
Function:%
\parbox[t]{3cm}{
\begin{itemize}[nosep]%
#1%
\end{itemize}
}
Data:%
\parbox[t]{3cm}{
\begin{itemize}[nosep]%
#2%
\end{itemize}%
}
}
\begin{document}
\begin{longtable}{p{0.3\textwidth}|p{0.7\textwidth}}
\caption[List of components]{List of functions and data allocated to each component} \label{d_plan} \\
\toprule
\textbf{Components} & \textbf{Functions and Data} \\\midrule
\textbf{Registration} & \fuda{
\item A
\item B
\item C
}{
\item  X
\item Y
\item  Z}
\\\bottomrule
\end{longtable}
\end{document}


You have a column of type p{...}. You don't need all these parboxes. This definition of your command will work without problems:

\newcommand{\fuda}[2]{%
Function:
\begin{itemize}[nosep]%
#1%
\end{itemize}
Data:
\begin{itemize}[nosep]%
#2%
\end{itemize}%
}