Comparison for two rows of same record data

So you can write you own (in Appian). Here's some initial guidance:

• use a!keys() on your first record instance to extract the record attributes
• for each extracted attribute, test if recordA[fv!item] = recordB[fv!item]  - if it does, it's a match. If it doesn't then it's not (you could out put the actual values in either or both cases if you wished
• either way, you can generate a map() with attributes that contain the result, and the values from each record's corresponding attribute 
• because you can define an expression with rule inputs of 'Any Type' then you could pass in your record instances of any type into that expression and you'd have the generic solution you're looking for

Out of curiosity, what is the use case here? Are you looking to provide an audit solution that compares two different versions of the data between two rows of data (read into Appian as records)? If so, there's still a missing piece of the puzzle. You will need to be able to map each record/attribute's technical name to a name a business auditor would recognize so that you can present this to an end-user.

We are using a similar approach. Have a look at it.
I am not sure about your use case, but I hope this helps with what you are expecting.
Happy to discuss your use case if this is not what you are looking for.
We created reusable expression.
Inputs:
1) oldRecord (Define ri! as AnyType)
2) newRecord (Define ri! as AnyType)

a!localVariables(
  local!allFields: union(
    a!keys(ri!oldRecord),
    a!keys(ri!newRecord)
  ),
  local!differences: reject(
    a!isNullOrEmpty,
    a!forEach(
      items: local!allFields,
      expression: a!localVariables(
        local!fieldName: fv!item,
        local!oldValue: index(ri!oldRecord, local!fieldName, null),
        local!newValue: index(ri!newRecord, local!fieldName, null),
        local!oldText: if(
          isnull(local!oldValue),
          "",
          tostring(local!oldValue)
        ),
        local!newText: if(
          isnull(local!newValue),
          "",
          tostring(local!newValue)
        ),
        local!isDifferent: if(
          and(
            isnull(local!oldValue),
            isnull(local!newValue)
          ),
          false,
          if(
            or(
              isnull(local!oldValue),
              isnull(local!newValue)
            ),
            true,
            not(exact(local!oldText, local!newText))
          )
        ),
        if(
          local!isDifferent,
          a!map(
            fieldName: local!fieldName,
            oldValue: if(
              isnull(local!oldValue),
              null,
              local!oldValue
            ),
            newValue: if(
              isnull(local!newValue),
              null,
              local!newValue
            ),
            changeType: if(
              and(
                isnull(local!oldValue),
                not(isnull(local!newValue))
              ),
              "ADDED",
              and(
                not(isnull(local!oldValue)),
                isnull(local!newValue)
              ),
              "REMOVED",
              "MODIFIED"
            ),
            dataType: typeof(local!newValue)
          ),
          null
        )
      )
    )
  ),
  /* Count changes manually */
  local!addedCount: length(
    where(
      a!forEach(
        items: local!differences,
        expression: index(fv!item, "changeType", "") = "ADDED"
      )
    )
  ),
  local!modifiedCount: length(
    where(
      a!forEach(
        items: local!differences,
        expression: index(fv!item, "changeType", "") = "MODIFIED"
      )
    )
  ),
  local!removedCount: length(
    where(
      a!forEach(
        items: local!differences,
        expression: index(fv!item, "changeType", "") = "REMOVED"
      )
    )
  ),
  a!map(
    recordType: typeof(ri!oldRecord),
    hasChanges: length(local!differences) > 0,
    totalChanges: length(local!differences),
    differences: local!differences,
    totalFields: length(local!allFields),
    summary: a!map(
      fieldsAdded: local!addedCount,
      fieldsModified: local!modifiedCount,
      fieldsRemoved: local!removedCount
    )
  )
)

For what purpose? What do you want to achieve with the results?