public static String extractScriptName(String propertyName) {
        if (propertyName.startsWith(RANKEXPRESSION) && propertyName.endsWith(RANKINGSCRIPT)) {
            return propertyName.substring(RANKEXPRESSION.length(), propertyName.length() - RANKINGSCRIPT.length());
        }
        return null;
    }
Returns the rank-property name for a given expression name.

@param expressionName the expression name to mangle.
@return the property name.
searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/RankingExpression.java