list environment to set different paragraphs within an item

Question

I'm trying to create a document with exercies and solutions. Since exercises often come in different parts (such as (a), (b) and so on), I want to use lists for the solutions. However, solutions are often complicated and need some formatting to be well understable. Therefore I need a list environment with flexible formatting such as stetting different paragraphs within an item.

I am using enumitem, but the inline list environment enumerate* doesn't accept paragraphs and seems to cause other minor problems. What alternatives do I have?

Here is a piece of code:

\begin{solution}
  \begin{enumerate*}[label=(\alph*)]
    \item {Text with, separated by an empty line

    to set a new paragraph}
  \end{enumerate*}
\end{solution}

An this is the output I get:

Here is a full minimal example:

\documentclass{scrreprt}

\PassOptionsToPackage{amsmath,thmmarks,thref}{ntheorem}
\PassOptionsToPackage{inline}{enumitem}

\usepackage{amsmath,MnSymbol}   
\usepackage{ntheorem,thmtools}
\usepackage{
    enumitem,
}

\declaretheoremstyle{plain}
\declaretheorem[style=plain,numbered=no,name=Proof]{proof}

\begin{document}

\begin{proof}
  \begin{enumerate*}[label=(\alph*),mode=unboxed]

    \item {A text

      separated by an empty line}
  \end{enumerate*}
\end{proof}

\end{document}

Again, here is my output:

Answer 1

I am not sure of I understand your question correctly. Using the series concept (refer to the package documentation for further details) you can use a standard enumerate environment when you need paragraphs and then enumerate* when you want an in-line enumeration, but using resume=<series-name> to keep the numbering consistent:

\documentclass{scrreprt}

\PassOptionsToPackage{amsmath,thmmarks,thref}{ntheorem}
\PassOptionsToPackage{inline}{enumitem}

\usepackage{amsmath,MnSymbol}   
\usepackage{ntheorem,thmtools}
\usepackage{enumitem}

\declaretheoremstyle{plain}
\declaretheorem[style=plain,numbered=no,name=Proof]{proof}

\begin{document}

\begin{proof}
  \begin{enumerate}[series=a,label=(\alph*),mode=unboxed]
    \item A text

      separated by an empty line
  \end{enumerate}
  \begin{enumerate*}[resume=a,label=(\alph*),mode=unboxed]
    \item A text
    \item A text
  \end{enumerate*}
\end{proof}

\end{document}

Answer 2

Since you asked for alternatives, it works with plain TeX's \item:

\item{1.} {Text with, separated by an empty line

    to set a new paragraph}

\bye