documentclass{book}
newcounter{foo}

begin{document}
tableofcontents
providecommand{foo1}{0}
providecommand{foo2}{0}

foo1 foo2

stepcounter{foo}
addtocontents{toc}{protectnewcommand{detokenize{foo}thefoo}{thepage}}

text

stepcounter{foo}
addtocontents{toc}{protectnewcommand{detokenize{foo}thefoo}{thepage}}

text
end{document}