How to reliably check if a document variable is not empty in ConTeXt?











up vote
3
down vote

favorite












Consider the following MWE:



startdocument[title=]

  doifemptyvariableelse{document}{title}{True}{documentvariable{title}}

  Test

stopdocument


So basically I have a document with a title variable. Now I want to check if that variable is empty (doifemptyvariableelse). Instead of simply outputting the right branch and exiting the current code gobbles the next two tokens, which feels wrong.



Is there some easy approach to check whether a document variable is empty that does not gobble following tokens?






context







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  • @Marco Well, I usually consult setup-en.pdf to see the available commands and it does not list doifdocumentvariable. The wiki also does not mention the new commands. Would you like to add an answer?
    – TeXnician
    Nov 18 at 16:19










  • Done. I can't for sure say why doifemptyvariable doesn't work in this case. It has something to do with how the argument is constructed, I believe. But I leave that part to the experts.
    – Marco
    Nov 18 at 16:31










  • a) doifemptyvariableelse doesn’t work because there is a bug (wrong number of arguments) for the TRUE case. b) The commands will be added to setup-en.pdf (If you miss a command in the document you can send a message to the ConTeXt mailing list or the author of the document).
    – Wolfgang Schuster
    Nov 18 at 22:34















up vote
3
down vote

favorite












Consider the following MWE:



startdocument[title=]

  doifemptyvariableelse{document}{title}{True}{documentvariable{title}}

  Test

stopdocument


So basically I have a document with a title variable. Now I want to check if that variable is empty (doifemptyvariableelse). Instead of simply outputting the right branch and exiting the current code gobbles the next two tokens, which feels wrong.



Is there some easy approach to check whether a document variable is empty that does not gobble following tokens?






context







share|improve this question






















  • @Marco Well, I usually consult setup-en.pdf to see the available commands and it does not list doifdocumentvariable. The wiki also does not mention the new commands. Would you like to add an answer?
    – TeXnician
    Nov 18 at 16:19










  • Done. I can't for sure say why doifemptyvariable doesn't work in this case. It has something to do with how the argument is constructed, I believe. But I leave that part to the experts.
    – Marco
    Nov 18 at 16:31










  • a) doifemptyvariableelse doesn’t work because there is a bug (wrong number of arguments) for the TRUE case. b) The commands will be added to setup-en.pdf (If you miss a command in the document you can send a message to the ConTeXt mailing list or the author of the document).
    – Wolfgang Schuster
    Nov 18 at 22:34













up vote
3
down vote

favorite









up vote
3
down vote

favorite











Consider the following MWE:



startdocument[title=]

  doifemptyvariableelse{document}{title}{True}{documentvariable{title}}

  Test

stopdocument


So basically I have a document with a title variable. Now I want to check if that variable is empty (doifemptyvariableelse). Instead of simply outputting the right branch and exiting the current code gobbles the next two tokens, which feels wrong.



Is there some easy approach to check whether a document variable is empty that does not gobble following tokens?






context







share|improve this question













Consider the following MWE:



startdocument[title=]

  doifemptyvariableelse{document}{title}{True}{documentvariable{title}}

  Test

stopdocument


So basically I have a document with a title variable. Now I want to check if that variable is empty (doifemptyvariableelse). Instead of simply outputting the right branch and exiting the current code gobbles the next two tokens, which feels wrong.



Is there some easy approach to check whether a document variable is empty that does not gobble following tokens?






context




context






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked Nov 18 at 15:23









TeXnician

23.4k62984




23.4k62984












  • @Marco Well, I usually consult setup-en.pdf to see the available commands and it does not list doifdocumentvariable. The wiki also does not mention the new commands. Would you like to add an answer?
    – TeXnician
    Nov 18 at 16:19










  • Done. I can't for sure say why doifemptyvariable doesn't work in this case. It has something to do with how the argument is constructed, I believe. But I leave that part to the experts.
    – Marco
    Nov 18 at 16:31










  • a) doifemptyvariableelse doesn’t work because there is a bug (wrong number of arguments) for the TRUE case. b) The commands will be added to setup-en.pdf (If you miss a command in the document you can send a message to the ConTeXt mailing list or the author of the document).
    – Wolfgang Schuster
    Nov 18 at 22:34


















  • @Marco Well, I usually consult setup-en.pdf to see the available commands and it does not list doifdocumentvariable. The wiki also does not mention the new commands. Would you like to add an answer?
    – TeXnician
    Nov 18 at 16:19










  • Done. I can't for sure say why doifemptyvariable doesn't work in this case. It has something to do with how the argument is constructed, I believe. But I leave that part to the experts.
    – Marco
    Nov 18 at 16:31










  • a) doifemptyvariableelse doesn’t work because there is a bug (wrong number of arguments) for the TRUE case. b) The commands will be added to setup-en.pdf (If you miss a command in the document you can send a message to the ConTeXt mailing list or the author of the document).
    – Wolfgang Schuster
    Nov 18 at 22:34
















@Marco Well, I usually consult setup-en.pdf to see the available commands and it does not list doifdocumentvariable. The wiki also does not mention the new commands. Would you like to add an answer?
– TeXnician
Nov 18 at 16:19




@Marco Well, I usually consult setup-en.pdf to see the available commands and it does not list doifdocumentvariable. The wiki also does not mention the new commands. Would you like to add an answer?
– TeXnician
Nov 18 at 16:19












Done. I can't for sure say why doifemptyvariable doesn't work in this case. It has something to do with how the argument is constructed, I believe. But I leave that part to the experts.
– Marco
Nov 18 at 16:31




Done. I can't for sure say why doifemptyvariable doesn't work in this case. It has something to do with how the argument is constructed, I believe. But I leave that part to the experts.
– Marco
Nov 18 at 16:31












a) doifemptyvariableelse doesn’t work because there is a bug (wrong number of arguments) for the TRUE case. b) The commands will be added to setup-en.pdf (If you miss a command in the document you can send a message to the ConTeXt mailing list or the author of the document).
– Wolfgang Schuster
Nov 18 at 22:34




a) doifemptyvariableelse doesn’t work because there is a bug (wrong number of arguments) for the TRUE case. b) The commands will be added to setup-en.pdf (If you miss a command in the document you can send a message to the ConTeXt mailing list or the author of the document).
– Wolfgang Schuster
Nov 18 at 22:34










1 Answer
1






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up vote
4
down vote



accepted










You can use doifdocumentvariableelse (defined in file-job.mkvi), which uses doifsomething. Example:



startdocument[title=]

  doifdocumentvariableelse{title}{documentvariable{title}}{False}



  %% is the same as:

  %% doifsomethingelse{documentvariable{title}}{documentvariable{title}}{False}



  Test

stopdocument





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    up vote
    4
    down vote



    accepted










    You can use doifdocumentvariableelse (defined in file-job.mkvi), which uses doifsomething. Example:



    startdocument[title=]
    
  doifdocumentvariableelse{title}{documentvariable{title}}{False}
    

    
  %% is the same as:
    
  %% doifsomethingelse{documentvariable{title}}{documentvariable{title}}{False}
    

    
  Test
    
stopdocument





    share|improve this answer

























      up vote
      4
      down vote



      accepted










      You can use doifdocumentvariableelse (defined in file-job.mkvi), which uses doifsomething. Example:



      startdocument[title=]
      
  doifdocumentvariableelse{title}{documentvariable{title}}{False}
      

      
  %% is the same as:
      
  %% doifsomethingelse{documentvariable{title}}{documentvariable{title}}{False}
      

      
  Test
      
stopdocument





      share|improve this answer























        up vote
        4
        down vote



        accepted







        up vote
        4
        down vote



        accepted






        You can use doifdocumentvariableelse (defined in file-job.mkvi), which uses doifsomething. Example:



        startdocument[title=]
        
  doifdocumentvariableelse{title}{documentvariable{title}}{False}
        

        
  %% is the same as:
        
  %% doifsomethingelse{documentvariable{title}}{documentvariable{title}}{False}
        

        
  Test
        
stopdocument





        share|improve this answer












        You can use doifdocumentvariableelse (defined in file-job.mkvi), which uses doifsomething. Example:



        startdocument[title=]
        
  doifdocumentvariableelse{title}{documentvariable{title}}{False}
        

        
  %% is the same as:
        
  %% doifsomethingelse{documentvariable{title}}{documentvariable{title}}{False}
        

        
  Test
        
stopdocument






        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered Nov 18 at 16:29









        Marco

        23.9k26797




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