How can I highlight an interactive GAP session just like so?

Question

Suppose I want to typeset a screen session in some programming language (GAP in my case, but it could be Python, BASH, or something else with an interactive read prompt just as well). So on my screen, I might have something like this:

gap> for i in [1..10] do
>   Print(i, ":");
> od;
1:2:3:4:5:6:7:8:9:10:
gap> 2^10;
1024
gap> 1/0;
Error, Rational operations: <divisor> must not be zero
not in any function at line 5 of *stdin*
you can replace <divisor> via 'return <divisor>;'
brk> 2^10;
1024
brk>

That is, there is a command prompt gap>, after which the user enters a multi line input. After that comes a line of output, then another prompt gap>. This repeats, until a command triggers an error, at which point the prompt changes to brk>.

I would like to use the listings package (or something else) to

1. color the prompts gap>, >, and brk>; say, blue and red;
2. highlight keywords like for, do, and od; say, by making them bold;
3. but only highlight the keywords in lines starting with a prompt, hence not inside the output of my commands.

The last point is the one that is causing me troubles. I couldn't figure out a way to do that. The result is often quite ugly when words like and, not, and in are highlighted as keywords in, e.g., an error message.

Similar questions have been asked before, but of those I managed to find, none asked for exactly this, resp. got an answer that does what I want.

For the record, here is the language definition I am using for now:

\lstdefinelanguage{GAP}{%
    morekeywords=[2]{and,break,continue,do,elif,else,end,fail,false,fi,for,%
        function,if,in,local,mod,not,od,or,rec,repeat,return,then,true,%
        until,while},%
    moredelim=[s][\color{blue}]{gap}{>},%
    moredelim=[s][\color{red}]{brk}{>},%
    %moredelim=*[l][\color{blue}]{gap>},%
    %moredelim=*[l][\color{red}]{brk>},%
    sensitive=true,%
    morecomment=[l]\#,%
    morestring=[b]',%
    morestring=[b]",%
    }%

PS: To illustrate what I want, consider this image showing how my example from above could look (in addition to what I described above, I also set all user inputs in italics):

Answer 1

This listings answer is about a year late, but I believe it covers all your requirements.

Edit: fixed a bug related to prompt "keywords" occurring in the middle of a line.

Desired output

Output obtained

Code

\documentclass[a4paper]{article}
\usepackage{xcolor}
\usepackage{textcomp}
\usepackage{listings}

\makeatletter

% switch to remember whether a prompt was found on the current line
\newif\ifprompt@GAP@
% switch to flag whether a prompt `keyword' is an bona fide GAP prompt
\newif\iftoolateforprompt@GAP@

% style of GAP keywords
\definecolor{GAPkeywords}{RGB}{077,145,021}
\newcommand\GAPkeywordstyle{\color{GAPkeywords}}

% font shape of GAP input lines 
\newcommand\GAPinputfshape\slshape

\lstdefinelanguage{GAP}
{%
  basicstyle =\ttfamily,
  alsoletter=>,
  morekeywords=[2]{%
    and,break,continue,do,elif,else,end,fail,false,fi,for,function,if,in,%
    local,mod,not,od,or,rec,repeat,return,then,true,until,while,
  },%
  keywordstyle=[2]\Process@GAP@keywords,
  morekeywords=[3]{gap>,>},
  keywordstyle=[3]\Process@GAP@prompt{blue},
  morekeywords=[4]{brk>},
  keywordstyle=[4]\Process@GAP@prompt{red},
  sensitive=true,%
  upquote=true,% <--- for straight single quotes
  showstringspaces=false,
  morecomment=[l]\#,
  morestring=[b]',
  morestring=[b]",
}%

% only highlight keywords if a prompt has occured on the current line
\newcommand\Process@GAP@keywords{\ifprompt@GAP@\GAPkeywordstyle\fi}

\newcommand\Process@GAP@prompt[1]
{%
  \iftoolateforprompt@GAP@%
  \else%
      \color{#1}\upshape% customise the style of your > and gap> prompts here
      \global\prompt@GAP@true%
      \aftergroup\GAPinputfshape% we trigger slanted shape after > or gap>
  \fi%
}

% Hook into InitVarsEOL (some hook executed right after an EOL) to:
% - reset the \ifprompt@GAP@ and \iftoolateforprompt@GAP@ switches
% - reset the font shape to \upshape
\lst@AddToHook{InitVarsEOL}%
{%
  \global\prompt@GAP@false%
  \global\toolateforprompt@GAP@false%
  \upshape%
}

% Hook into PostOutput to signal that a GAP prompt
% can no occur on the current line
\lst@AddToHook{PostOutput}{\global\toolateforprompt@GAP@true}

\makeatother

\begin{document}
\begin{lstlisting}[language=GAP]
gap> for i in [1..10] do
>   Print(i, ":");
> od;
1:2:3:4:5:6:7:8:9:10:
gap> 2^10;
1024
gap> 1/0;
Error, Rational operations: <divisor> must not be zero
not in any function at line 5 of *stdin*
you can replace <divisor> via 'return <divisor>;'
brk> 2^10;
1024
brk>
\end{lstlisting}
\end{document}

Answer 2

The one drawback is that I process whole words, not subwords. Thus, od; is a separate word from od. That can be overcome, but not in this MWE. I copied your raw (unformatted) session output into the file session.in and went from there.

\documentclass[12pt]{article}
\makeatletter%
\let\protectededef\protected@edef
\makeatother%

\parindent 0in
\renewcommand{\encodingdefault}{T1}
\usepackage{color}
\usepackage{readarray}
\usepackage{verbatimbox}
\usepackage{ifthen}
\catcode`^=12
\definecolor{darkgreen}{rgb}{0,0.5,0}
\newcounter{rowindex}\newcounter{wordindex}%

\newcommand\displaysource[1]{%
  \sffamily%
  \readdef{#1}{\x}%
  \setcounter{rowindex}{0}%
  \whiledo{\value{rowindex} < \nrecords}{%
    \addtocounter{rowindex}{1}%
    \getargsC{\csname record\roman{rowindex}\endcsname}%
    \ifthenelse{\equal{\argi}{>}  \OR%
                \equal{\argi}{gap>}  \OR%
                \equal{\argi}{brk>}}%
                {\def\userin{\itshape}}{\def\userin{\upshape}}%
    \setcounter{wordindex}{0}%
    \whiledo{\value{wordindex} < \narg}{%
      \addtocounter{wordindex}{1}%
      \protectededef\thisword{\csname arg\roman{wordindex}\endcsname}%
      \ifthenelse{\equal{\thisword}{gap>}  \OR%
                  \equal{\thisword}{>}}%
        {%
          \upshape\textcolor{blue}{\thisword~}%
        }{%
          \ifthenelse{\equal{\thisword}{brk>}}%
            {%
              \textcolor{red}{brk>~}%
            }{%
              \userin%
              \ifthenelse{\equal{\thisword}{for}  \OR%
                          \equal{\thisword}{in}  \OR%
                          \equal{\thisword}{do}  \OR%
                          \equal{\thisword}{od}  \OR%
                          \equal{\thisword}{od;}}%
              {%
                \ifthenelse{\equal{\userin}{\itshape}}%
                  {%
                    \textcolor{darkgreen}{\thisword~}%
                  }{%
                    \thisword~%
                  }%
              }{%
                \thisword~%
              }
            }%
        }%
    }%
    \\%
  }%
  \rmfamily%
}
\begin{document}

\displaysource{session.in}

\end{document}