ConTeXt and Lua programming/Counters

ConTeXt provides a higher layer of API to access various counters. For example, to set the page number to a certain value use \setcounter:

 \setcounter[userpage][1]

Other useful commands for working with counters are

• \resetcounter
• \incrementcounter
• \decrementcounter
• \savecounter
• \restorecounter
• \rawcountervalue (not \getcounter)
• \setupheadnumber

Names of Commonly Used Counters

• userpage for visible pagenumbers
• page for internal pagenumbers
• formula for formula numbers
• table for table numbers
• figure for figure numbers

Testing the Value of a Counter

If you need to test the value of a counter, use \rawcountervalue (the is no \getcounter):

• \definecounter [mynumber] []
  \setcounter [mynumber] [42]
  
  \doifelse
    {\rawcountervalue[mynumber]}
    {42}
    {First test is OK}
    {Failed}
  

  results in:

• 

Coupling Counters

Two counters can be coupled by

 \definecounter[one]
 \definecounter[two][one]

For example

• \definecounter[one]
  \definecounter[two][one]
  
  Default value of counter one:
  \rawcountervalue[one]
  
  We increment counter two
  \incrementcounter[two]
  
  New value of counter one:
  \rawcountervalue[one]
  

• 

By default counters are reset with each new chapter. To have a counter which isn’t reset you need way=bytext, and to remove the chapter number from the \getcounter result you have to add prefix=no.

Example definition:

\definecounter[examplecounter][way=bytext,prefix=no]