Variables in XSL are not like the variables you have come across in other programming environments. In XSL, the term variable is used in its mathematical sense to mean a placeholder. This means that, once defined, a variable cannot be changed.
It is possible to override a variable in certain contexts. To do this correctly you need to have a good understanding of XSLT import precedence. The variables defined in std_variables provide access to environment parameters and specific parts of the source lxml data. If you need to change the default value of a variable then change the source data rather than the variable.
If you wish to create your own variables then create your own xxx_variables weblet and import it into your layouts or weblets as required.
We do not recommend that you change the std_variables weblet as this may be changed by future updates.
If you reinstall Visual LANSA, any changes made to the standard shipped weblets will be overwritten.