macro for hyperref package so that it returns a result like 1-3,5-7,9,11-12 instead of 1,2,3,5,6,7,9,11,12

Question

I would like to request your help with the following: With the package hyperref I get a lot of backreferences in my bibliography like 1,1,1,2,2,3,5,8,9,10,11,11,11,12,12,13,17,19 Now I wanted to write a macro that turns this result into: 1-3,5,8-13,17,19 if Kind = 0 1,3;2,2;3;5;8;9;10;11,3;12,2;13;17;19 if Kind = 1 where Kind is a variable to have a certain layout according to your choice When I run the file PROBEERTEST.TEX the above examples are correct but the bottom one has a lot of 'I assume spaces' in front of it (I have tried adding % after each line and removing all spaces but I still get those spaces). Can anyone help me (I want that the aa is followed immediately by the result and not with this free room after it)

• FILE PROBEER.TEX *

   % To turn 1,1,1,2,2,3,5,8,9,10,11,11,11,12,12,13,17,19 into
   %         1-3,5,8-13,17,19 if Kind = 0
   % To turn 1,1,1,2,2,3,5,8,9,10,11,11,11,12,12,13,17,19 into
   %         1,3;2,2;3;5;8;9;10;11,3;12,2;13;17;19 if Kind = 1
   % Based on TeX by Topic p 105
  
  \newcount\Kind % 0: like 1--3,5,7,10--12,
         % 1: like 1,2;3,2;number,# of number; 
  \newcount\CountP % Previous
  \newcount\CountN % Next
  \newcount\CountT % Temp
  \newcount\CTimes % Number of times 
  \newcount\State % 3: using kind=1 after reading in
                  %    first element (state=2)
                  % 2: start, first element printed
                  % 1: during {--}.
                  % 0: otherwise (non-sequential)
  \CountP=-10000
  \CTimes=0
  \Kind=0
  
  % --- begin TO STORE THE RESULT 
  
  \def\ResultDef{} % def to hold the result
  
  % USING DEF TO STORE THE RESULT
  
  \def\addToResultDef#1{
  \edef\ResultDef{\ResultDef #1}
  }
  
  \def\printResultDef{
  \ResultDef
  }
  
  % --- end TO STORE THE RESULT
  
  \def\Combine#1{\xCombine#1,xxx, 
  \printResultDef
  \CountP=-10000
  \CTimes=0
  \def\ResultDef{}
  }   
  
  \def\endpiece{xxx}
  
  \def\xCombine#1,{\def\temp{#1}
  \ifx\temp\endpiece
    \advance \CountN by 3 % to process the last element
    \Process{\the\CountN}
  \else \Process{#1} 
        \expandafter \xCombine 
  \fi}
  
  \def\Process#1{
  \CountN=#1
  \ifnum\CountP=-10000
    \CountP=\CountN
    \State=2
    \advance \CTimes by 1
    %\the\CountP
    \addToResultDef{\the\CountP}
  \else
    \ifnum\CountP=\CountN
       \advance \CTimes by 1
    \else             % \CountP<\CountN
       \ifnum\Kind=0     
          \ProcessA{#1} 
       \else
          \ProcessB{#1} 
       \fi
       \CTimes=1
       \CountP=\CountN
    \fi
  \fi
  }
  
  \def\ProcessA#1{ % \Kind=0
  \CountT=\CountP
  \advance\CountT by 1
  \ifnum\CountN=\CountT
    \ifnum\State=0
      %\the\CountP
      \addToResultDef{,\the\CountP}
    \fi
    \State=1
  \else
    \ifnum\State=0
      %, \the\CountP
      \addToResultDef{,\the\CountP}
    \else
      \ifnum\State=1
         %{--} \the\CountP
         \addToResultDef{{--}\the\CountP}
         \State=0
      \else 
        \ifnum\State=2
          \State=0
        \else
          \typeout{Invalid State!!}
        \fi
      \fi
    \fi
  \fi
  }
  
  \def\ProcessB#1{ % \Kind=1
   \ifnum\State=2
      \ifnum\CTimes=1
      \else
        \addToResultDef{,\the\CTimes}
      \fi
      \State=3
   \else % State=3
      \ifnum\CTimes=1
        \addToResultDef{;\the\CountP}
      \else
        \addToResultDef{;\the\CountP,\the\CTimes}
      \fi
   \fi
  }
  

• FILE PROBEERTEST.TEX *

  %% To test probeer.tex in TeX itself to see if it works accordonly
  \magnification\magstep1
  \hsize 5.5 true in
  \hoffset 0.5 true in
  \vsize 8.25 true in
  \voffset = 2\baselineskip
  \vbadness11000
  
  \input probeer
  
  \noindent 1,1,1,2,3,4,5,6,7,11,12,13,15,17 \hfill \break 
  becomes \hfill \break
  \Combine{1,1,1,2,3,4,5,6,7,11,12,13,15,17} \hfill \break
  \hfill
  
  \noindent New attempt: \hfill \break
  1,2,3,4,5,6,7,11,12,12,13,15,17,17,21,22,23 \hfill \break  
  becomes \hfill \break 
  \Combine{1,2,3,4,5,6,7,11,12,12,13,15,17,17,21,22,23} \hfill \break
  \hfill
  
  \vbox{
  \hbox to \hsize{1,2,3,4,5,5,6,7,11,12,13,15,17,21,22,23 \hfill}
  \hbox to \hsize {becomes \hfill}
  \hbox to \hsize{aa\Combine{1,2,3,4,5,5,6,7,11,12,13,15,17,21,22,23}bb \hfill}
  \vfill}
  
  \bye
  

Answer 1

Every non-macro, in particular { or } that are followed by a newline inside of a macro definition create a space.

If you don't believe those are responsible, you can put

\endlinechar=-1

at the top of your file and

\endlinechar=13

at the bottom to revert to the previous behavior. In this particular case, you'll have to watch for the 'reverse' problem then: you have several numbers that actually are properly terminated by that end of line and that no longer will be so. You can fix that by writing something like

\ifnum\State=1 %

And the space before the comment sign will be visible even with end line characters switched off.

I have to agree with the comment of wasteofspace though: it is not obvious where this combined hyperlink should be pointing.