How can I react to event on system variable defined in CAPL script?

I defined a system variable in my CAPL file that I use to set up different modes in my script.

I declared it in my CAPL file and not in my CANAlyzer window in order to allow the script to work with different configs.

sysDefineNamespace("NameSpace");

sysDefineVariableInt("NameSpace","VariableName",0);

The declaration has worked because I can change the value of this system variable with on key events.

The problem is with on sysvar events, the syntax that I saw on the internet is not working. I use this one:

on sysvar NameSpace::VariableName{
  sysSetVariableInt("NameSpace","VariableName",0); //init tout à off
}

I get a compilation error :

Compiling...
Options: CANalyzer, Realtime
Name (1, 11) Error 1249: Variable name 'NameSpace' not found
Compilation errors.

I'm pretty sure it is a syntax error but I didn't manage to fix it.

Thank you for your help !

I tried to change the syntax several time without success.