lstinline inside new environment not able to escape maths

Question

I am trying to create a new environment using \lstinline from the listings package. But it does not escape maths.

I have tried solutions in a couple of questions - 1, 2, but not able to get it working for my problem.

Below is the code that I am trying and its output

\documentclass[12pt,a4paper]{article}
\usepackage{listings}
\usepackage{parskip}
\lstset{mathescape,keepspaces}

\newenvironment{newEnv}[1]{\lstinline[basicstyle=\bfseries\ttfamily,escapeinside={||},mathescape=true]{#1}\\
}
{}

\begin{document}
    \lstinline{let $v_1$ = 10 in $v_1$ + $v_2$}

    \begin{newEnv}{let $v_1$ = 10 in $v_1$ + $v_2$}
      Some random text.
    \end{newEnv}
\end{document}

Output

Update: LaTeX escape not working

\documentclass[12pt,a4paper]{article}
\usepackage{listings}
\usepackage{parskip}
\lstset{mathescape,keepspaces}

\NewDocumentEnvironment{newEnv}{v}
  {%
    \begingroup
    \everyeof{\noexpand}%
    \expandafter
    \endgroup
    \scantokens
      {%
        \lstinline
          [basicstyle=\bfseries\ttfamily,escapeinside=||,mathescape=true]%
          {#1}%
      }%
    \\
  }
  {}

\begin{document}
    \lstinline
      [basicstyle=\bfseries\ttfamily,escapeinside=||,mathescape=true]%
      {let $v_1$ = 10 in $v_1$ + $v_2$ |this should be escaped\textsuperscript{3}|}

    \begin{newEnv}{let $v_1$ = 10 in $v_1$ + $v_2$ |this should be escaped\textsuperscript{3}|}
      Some random text.
    \end{newEnv}
\end{document}

Output

Answer 1

The following works by grabbing the argument verbatim and forwarding that to \lstinline (wrapped inside \scantokens so that \lstinline can assign whichever category codes it needs).

This solution only works for single-line verbatim arguments. If you need it to work for multi-line arguments as well I can adapt things (but it's a bit more work).

\documentclass[12pt,a4paper]{article}
\usepackage{listings}
\usepackage{parskip}
\lstset{mathescape,keepspaces}

\NewDocumentEnvironment{newEnv}{v}
  {%
    \begingroup
    \everyeof{\noexpand}%
    \expandafter
    \endgroup
    \scantokens
      {%
        \lstinline
          [basicstyle=\bfseries\ttfamily,escapeinside={||},mathescape=true]%
          {#1}%
      }%
    \\
  }
  {}

\begin{document}
    \lstinline
      [basicstyle=\bfseries\ttfamily,escapeinside={||},mathescape=true]%
      {let $v_1$ = 10 in $v_1$ + $v_2$}

    \begin{newEnv}{let $v_1$ = 10 in $v_1$ + $v_2$}
      Some random text.
    \end{newEnv}
\end{document}