Set boolean of environment before a command

Question

A command must be put before an environment, defining the kind of environment. However, the first boolean does not execute, the result is wrong. Please help me fix the problem.

\documentclass[12pt]{article}
\usepackage{etoolbox}
\newbool{blbt}
\newbool{blvd}
%%%=======================
\newenvironment{bt}{\global\setbool{blvd}{false}\global\setbool{blbt}{true}\par}{}
%%%=======================
\newenvironment{vd}{\global\setbool{blvd}{true}\global\setbool{blbt}{false}\par}{}
%%%=======================
\newcommand{\classify}{The below environment is 
    \ifbool{blvd}{Example}{\ifbool{blbt}{Problem}{Wrong}}}
\begin{document}
{\bfseries\classify}
    \begin{bt}
     Contents PPP
    \end{bt}
    
{\bfseries\classify}
    \begin{vd}
     Contents EXEXEX
    \end{vd}
\end{document}

Answer 1

How about this?

\documentclass[12pt]{article}
\usepackage{etoolbox}
\newbool{blbt}
\newbool{blvd}
\newcommand{\classify}{The environment below is 
    \ifbool{blvd}{Example}{\ifbool{blbt}{Problem}{Wrong}}}
%%%=======================
\newenvironment{bt}{\global\setbool{blvd}{false}\global\setbool{blbt}{true}{\bfseries\classify}\par}{}
%%%=======================
\newenvironment{vd}{\global\setbool{blvd}{true}\global\setbool{blbt}{false}{\bfseries\classify}\par}{}
%%%=======================
\begin{document}
    \begin{bt}
     Contents PPP
    \end{bt}
    
    \begin{vd}
     Contents EXEXEX
    \end{vd}
\end{document}

Answer 2

If you don't mind your command \classify and your environments bt and vt to have a non-optional argument, then you can use the package zref and have

• the environments bt and vt place referencing-labels for properties blvd and blbt
• the command \classify extract values of properties from these referencing-labels:

\documentclass[12pt]{article}
\usepackage{etoolbox}
\usepackage{zref}

\makeatletter
\@ifdefinable\@zrefpropdefined{%
  \ZREF@Robust\def\@zrefpropdefined{%
    \zref@wrapper@babel\@ZREFpropdefined
  }%
}%
\@ifdefinable\@ZREFpropdefined{%
  \def\@ZREFpropdefined#1#2#3#4{%
    % #1  - label
    % #2  - property
    % #3  - tokens in case label and property are available
    % #4  - tokens in case label undefined or property not available
    \zref@ifrefundefined{#1}{%
       \zref@refused{#1}#4%
    }{%
      \zref@ifrefcontainsprop{#1}{#2}{#3}{%
        \protect\G@refundefinedtrue
        \@latex@warning{%
           Missing property `#2' in reference `#1' on page \thepage
        }%
        #4%
      }%
    }%
  }%
}%
\zref@newprop{blbt}{false}%
\zref@newprop{blvd}{false}%
\newcommand\blvdANDblbtLABEL[3]{%
  \zref@setcurrent{blvd}{#1}%
  \zref@setcurrent{blbt}{#2}%
  \zref@wrapper@immediate{%
    \zref@labelbyprops{#3}{blbt,blvd}%
  }%
}%
%%%=======================
\newenvironment{bt}[1]{%
  \blvdANDblbtLABEL{false}{true}{#1}%
  % Here you could place code that forks 
  % via \ifbool{\zref@getcurrent{blvd}}{<true>}{<false>}%
  % and \ifbool{\zref@getcurrent{blbt}}{<true>}{<false>}%
\par}{}
%%%=======================
\newenvironment{vd}[1]{%
  \blvdANDblbtLABEL{true}{false}{#1}%
  % Here you could place code that forks 
  % via \ifbool{\zref@getcurrent{blvd}}{<true>}{<false>}%
  % and \ifbool{\zref@getcurrent{blbt}}{<true>}{<false>}%
\par}{}
%%%=======================
\newcommand{\classify}[1]{The below environment is 
  \@zrefpropdefined{#1}{blvd}{%
    \@zrefpropdefined{#1}{blbt}{\@firstoftwo}{\@secondoftwo}%
  }{%
    \@zrefpropdefined{#1}{blbt}{}{}%
    \@secondoftwo
  }%
  {%
    \ifbool{\zref@extractdefault{#1}{blvd}{}}{Example}{%
      \ifbool{\zref@extractdefault{#1}{blbt}{}}{Problem}{Wrong}%
    }%
  }{%
    \nfss@text{\reset@font\bfseries??}%
  }%
}%
\makeatother

\begin{document}

{\bfseries\classify{Label Of This Environment}}
    \begin{bt}{Label Of This Environment}
     Contents PPP
    \end{bt}
    
{\bfseries\classify{Label Of That Environment}}
    \begin{vd}{Label Of That Environment}
     Contents EXEXEX
    \end{vd}

\end{document}

(If the real-life-scenario also is about only two environments, you could do with a single boolean if the \classify-command's wrong-case" can be omitted.)

Using zref you can probably do without boolean at all:

\documentclass[12pt]{article}
\usepackage{zref}

\makeatletter

\@ifdefinable\@zrefpropdefined{%
  \ZREF@Robust\def\@zrefpropdefined{%
    \zref@wrapper@babel\@ZREFpropdefined
  }%
}%
\@ifdefinable\@ZREFpropdefined{%
  \def\@ZREFpropdefined#1#2#3#4{%
    % #1  - label
    % #2  - property
    % #3  - tokens in case label and property are available
    % #4  - tokens in case label undefined or property not available
    \zref@ifrefundefined{#1}{%
       \zref@refused{#1}#4%
    }{%
      \zref@ifrefcontainsprop{#1}{#2}{#3}{%
        \protect\G@refundefinedtrue
        \@latex@warning{%
           Missing property `#2' in reference `#1' on page \thepage
        }%
        #4%
      }%
    }%
  }%
}%

\zref@newprop{environmentphrase}{unknown}%
\newcommand\environmentphraseLABEL[2]{%
  \zref@setcurrent{environmentphrase}{#1}%
  \zref@wrapper@immediate{%
    \zref@labelbyprops{#2}{environmentphrase}%
  }%
}%
%%%=======================
\newenvironment{bt}[1]{%
  \environmentphraseLABEL{Problem}{#1}%
\par}{}
%%%=======================
\newenvironment{vd}[1]{%
  \environmentphraseLABEL{Example}{#1}%
\par}{}
%%%=======================
\newcommand{\classify}[1]{The below environment is 
  \zref@extractdefault{#1}{environmentphrase}{%
    \@zrefpropdefined{#1}{environmentphrase}{%
      \protect\G@refundefinedtrue
      \@latex@warning{%
        Unspecified problem in reference `#1' on page \thepage
      }%
    }{}%
    \nfss@text{\reset@font\bfseries??}%
  }%
}%
\makeatother

\begin{document}

{\bfseries\classify{Label Of This Environment}}
    \begin{bt}{Label Of This Environment}
     Contents PPP
    \end{bt}
    
{\bfseries\classify{Label Of That Environment}}
    \begin{vd}{Label Of That Environment}
     Contents EXEXEX
    \end{vd}

\end{document}

With both examples you need two LaTeX-compilations (without having auxiliary-files deleted between these runs) for having everything match out.

With both examples the resulting .pdf-file looks like this:

Answer 3

\documentclass[12pt]{article}
\newif\ifblbt
\newif\ifblvd
\newenvironment{bt}
  {\blvdfalse\blbttrue{\bfseries\classify\par}}
  {}
\newenvironment{vd}
  {\blvdtrue\blbtfalse{\bfseries\classify\par}}
  {}
\newcommand\classify{The below environment is \ifblvd Example\else\ifblbt Problem\else Wrong\fi\fi}
\begin{document}
    \begin{bt}
     Contents PPP
    \end{bt}
    
    \begin{vd}
     Contents EXEXEX
    \end{vd}
\end{document}

Answer 4

Base on the @modnar's suggestion. Thank you very much for your helps!

\documentclass[12pt]{article}
\usepackage{etoolbox}
\newbool{blbt}
\newbool{blvd}
\newif\ifoutput
\newcommand{\classify}{\outputtrue}
\newcommand{\classifyp}{
\ifoutput{
The environment below is 
    \ifbool{blvd}{Example}{\ifbool{blbt}{Problem}{Wrong}}
    }\fi
}
%%%=======================
\newenvironment{bt}{\global\setbool{blvd}{false}\global\setbool{blbt}{true}{\bfseries\classifyp}\par}{}
%%%=======================
\newenvironment{vd}{\global\setbool{blvd}{true}\global\setbool{blbt}{false}{\bfseries\classifyp}\par}{}
%%%=======================
\begin{document}
\classify

    \begin{bt}
     Contents PPP
    \end{bt}
    
    \begin{vd}
     Contents EXEXEX
    \end{vd}
    
      \begin{bt}
         Contents PPP
        \end{bt}
\end{document}