Difference between revisions of "Counters"

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(some restructuring and cleanup)
 
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Line 4: Line 4:
  
 
<texcode>
 
<texcode>
−
  \setnumber[page]{1}
+
  \setcounter[userpage][1]
 
</texcode>
 
</texcode>
  
Line 10: Line 10:
  
 
<texcode>
 
<texcode>
−
     \resetnumber   [page]
+
     \resetcounter   [page]
−
     \incrementnumber[page]
+
     \incrementcounter[page]
−
     \decrementnumber[page]
+
     \decrementcounter[page]
−
     \savenumber     [page]
+
     \savecounter     [page]
−
     \restorenumber [page]
+
     \restorecounter [page]
−
     \getnumber      [page]
+
     %\getcounter    [page]
 +
    \rawcountervalue [page]
 
</texcode>
 
</texcode>
 +
 +
== Names of Commonly Used Counters ==
 +
 +
* <code>userpage</code> for visible pagenumbers
 +
* <code>page</code> for internal pagenumbers
 +
* <code>formula</code> for formula numbers
 +
* <code>table</code> for table numbers
 +
* <code>figure</code> for figure numbers
 +
 +
 +
== Testing the Value of a Counter ==
 +
 +
If you need to test the value of a counter, use \rawcountervalue, not \getcounter:
 +
 +
<context source="yes" text="results in:">
 +
\definecounter[mynumber][]
 +
\setcounter[mynumber][42]
 +
\doifelse{\getcounter[mynumber]}{42}{
 +
Strange, \type{\getcounter} worked.
 +
}{
 +
Using \type{\getcounter} does not work.
 +
}
 +
 +
\doifelse{\rawcountervalue[mynumber]}{42}{
 +
Ok, the test with \type{\rawcountervalue} worked.
 +
}{
 +
Strange, \type{\rawcountervalue} failed.
 +
}
 +
</context>
 +
 +
In LMTX, {{cmd|getcounter}} seems to be generally defunct.
  
 
== Coupling Counters ==
 
== Coupling Counters ==
Line 23: Line 55:
  
 
<texcode>
 
<texcode>
−
  \definenumber[one]
+
  \definecounter[one]
−
  \definenumber[two][one]
+
  \definecounter[two][one]
 
</texcode>
 
</texcode>
  
Line 30: Line 62:
  
 
<context source="yes">
 
<context source="yes">
−
\definenumber[one]
+
\definecounter[one]
−
\definenumber[two][one]
+
\definecounter[two][one]
  
  
−
Default value of counter one: \getnumber[one]
+
Default value of counter one: \rawcountervalue[one]
  
 
We increment counter two
 
We increment counter two
−
\incrementnumber[two]
+
\incrementcounter[two]
  
−
New value of counter one: \getnumber[one]
+
New value of counter one: \rawcountervalue[one]
  
 
</context>
 
</context>
  
−
By default counters are reset with each new chapter. To have a counter which isn’t reset one needs “way=bytext" and to remove the chapter number from the \getnumber result one has to add “prefix=no”.
+
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`.
  
−
An example definition is
+
Example definition:
 
<texcode>
 
<texcode>
−
\definenumber[examplecounter][way=bytext,prefix=no]
+
\definecounter[examplecounter][way=bytext,prefix=no]
 
</texcode>
 
</texcode>
  
−
== Testing the Value of a Counter ==
+
== Outdated information ==
−
If you need to test the value of a counter, use \rawcountervalue, not \getnumber:
+
 
 +
=== Forcing the Reset of a Counter ===
 +
 
 +
In [http://www.mail-archive.com/ntg-context%40ntg.nl/msg78847.html 2015], there was a bug that counters were reset (by chapter, page, etc.) only when they were incremented.
 +
 
 +
To force the reset, you can increment and then decrement a counter before using it.
 
<texcode>
 
<texcode>
−
\definenumber[mynumber][]
+
\definecounter[mycounter][way=bypage]
−
\setnumber[mynumber][42]
+
\setcounter[mycounter][10]
−
\doifelse{\getnumber[mynumber]}{42}{
+
\rawcountervalue[mycounter]
−
Strange, {\tt getnumber} worked.
+
\page                      % new page, mycounter should be reset
−
}{
+
\rawcountervalue[mycounter] % no, it's not reset: you still get '10'
−
Using {\tt getnumber} does not work.
 
−
}
 
  
−
\doifelse{\rawcountervalue[mynumber]}{42}{
+
\incrementcounter[mycounter]\decrementcounter[mycounter]
−
Ok, the test with {\tt rawcountervalue} worked.
+
\rawcountervalue[mycounter] % now you should get '0' because it has been reset
−
}{
 
−
Strange, {\tt rawcountervalue} failed.
 
−
}
 
 
</texcode>
 
</texcode>
  
−
== Names of Commonly Used Counters ==
+
=== \definenumber or \definecounter ? ===
 +
{{cmd|definenumber}} etc. are obsolete aliases for {{cmd|definecounter}} etc.
  
−
* <code>page</code> for pagenumbers
 
−
* <code>formula</code> for formulanumbers
 
−
* <code>table</code> for tables
 
−
* <code>figure</code> for figures
 
  
−
[[Category:Inside ConTeXt]]
+
[[Category:Programming and Databases]]
−
[[Category:ConTeXt programming]]
+
[[Category:Tools]]

Latest revision as of 06:16, 5 April 2024

< Main Page | Inside ConTeXt >

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

 \setcounter[userpage][1]

Other useful commands for working with counters are 

    \resetcounter    [page]
    \incrementcounter[page]
    \decrementcounter[page]
    \savecounter     [page]
    \restorecounter  [page]
    %\getcounter     [page]
    \rawcountervalue [page]

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, not \getcounter: 

\definecounter[mynumber][]
\setcounter[mynumber][42]
\doifelse{\getcounter[mynumber]}{42}{
 Strange, \type{\getcounter} worked.
}{
 Using \type{\getcounter} does not work.
}

\doifelse{\rawcountervalue[mynumber]}{42}{
 Ok, the test with \type{\rawcountervalue} worked.
}{
 Strange, \type{\rawcountervalue} failed.
}

results in:

In LMTX, \getcounter seems to be generally defunct.

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]

Outdated information

Forcing the Reset of a Counter

In 2015, there was a bug that counters were reset (by chapter, page, etc.) only when they were incremented.

To force the reset, you can increment and then decrement a counter before using it. 

\definecounter[mycounter][way=bypage]
\setcounter[mycounter][10]
\rawcountervalue[mycounter]
\page                       % new page, mycounter should be reset
\rawcountervalue[mycounter] % no, it's not reset: you still get '10'

\incrementcounter[mycounter]\decrementcounter[mycounter]
\rawcountervalue[mycounter] % now you should get '0' because it has been reset

\definenumber or \definecounter ?

\definenumber etc. are obsolete aliases for \definecounter etc.

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