Questions answered by this recipe
The CascadeVar() function is intended to be used as a helpful function to define page variables that are drawn from page text variables defined in specific pages. This makes it easy to create page variables that can have default values that can be overridden by authors for a specific page, group, or site. CascadeVar() will use the pages in $CascadeVarPathFmt, which will look in the current page, the GroupAttributes page, and the site's GroupAttributes page for the value of a given page variable. If not located in any of these sources, then the $CascadeVar array is used. To use this function, simply define a page variable in
$FmtPVthat calls the CascadeVar() function with a page name and the name of the page text variable to be used as a cascade variable. For example, to have $BannerTitle come from $:BannerTitle in the current page, GroupAttributes, or Site.GroupAttributes, one would define:
$FmtPV['$BannerTitle'] = 'CascadeVar($pn, "BannerTitle")';
If the recipe has multiple releases, then release notes can be placed here. Note that it's often easier for people to work with "release dates" instead of "version numbers".
See discussion at CascadeVar-Talk