Process Variables in SAIL form

To add on here - there have been times with PROD maintenance that might require accessing a PV directly from a SAIL form. For example, if you are maintaining an Appian instance that has been in PROD for a long time, there might be forms or expression rules that are called without named parameters (such as rule!testrule(pv!input1, pv!input2) rather than rule!testrule(input1: pv!input1, input2: pv!input2).

When this happens, adding extra inputs to the expression rule will break any process instances already in PROD, so you can use PV! directly on the SAIL form to access the variable. However, this is not a preferred method of doing it, and as @stefanh mentioned, becomes extremely tedious to maintain in the long-term. Especially for new development / applications not in PROD, the traditional inputs should be the only variables accessed on a form.

To add on here - there have been times with PROD maintenance that might require accessing a PV directly from a SAIL form. For example, if you are maintaining an Appian instance that has been in PROD for a long time, there might be forms or expression rules that are called without named parameters (such as rule!testrule(pv!input1, pv!input2) rather than rule!testrule(input1: pv!input1, input2: pv!input2).

When this happens, adding extra inputs to the expression rule will break any process instances already in PROD, so you can use PV! directly on the SAIL form to access the variable. However, this is not a preferred method of doing it, and as @stefanh mentioned, becomes extremely tedious to maintain in the long-term. Especially for new development / applications not in PROD, the traditional inputs should be the only variables accessed on a form.