When writing a rule in 'advance mode', you can use the following three options: constants, functions and variables.
Constants are fixed values. An example of a constant is the match type of a keyword (i.e. 'BROAD'). When you are referring to the value of the match type, you are referring to something that doesn't change and is therefore a constant.
Variables refer to characteristics, numbers, or quantities that are taken from AdWords. The terms that open up in each rule are related to the attribute you wish to change, as well as the parent attribute. An example of a variable is the number of impressions your keyword has accrued over a period of time (i.e. 'kwImpr'). This is something that is bound to change, and is therefore variable.
Functions are preset routines that perform certain tasks. You can use these functions to take certain actions on your requested parameters. These functions are normally built to do a certain task, the details of what the task it will do should be located in the r# reference of the Advanced Mode of Rule writing.
*Note: Rule writing can only be done on the Agency level plans and above.
To find the list of available functions for rule writing:
1. Make sure to be on the Campaigns tab, in 'Automation Rules' under the Optimize section.
Click on the + Add Rule button to open a drop down menu
2. Select the rule type you wish to implement (or select an arbitrary option)
3. Create a new empty rule by Clicking the '+ New Rule' Button.
4. Select 'Advanced Mode'
5. Click on the '#r reference' link
6. Functions are preset routines that perform certain tasks. You can use these functions to take certain actions on your requested parameters.
7. You can click on the question marks beside each function for a more detailed description.