Growing "case comments" field?

[Andrew Cawood]

Good day,

I'd like to implement a comment field for all my patient cases.
The idea is that any form which updates information for a patient case has a comment field at the end. This comment field should be appended (or pre-pended) to the existing comment field on the case.

An example of how this would look:
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1) On case creation form, comment: "Patient has high BP, should be monitored"

     #case/comment =
         "1 Mar 2017: Patient has high BP 145/90, should be monitored (chw1)"

2) On a follow-up form, comment: "BP improved slightly 140/85, keep monitoring."

     #case/comment =
         "1 Mar 2017: Patient has high BP 145/90, should be monitored (chw1)"
         "10 Mar 2017 BP improved slightly 140/85, keep monitoring. (chw2)"

3) On a follow-up form, comment: "Patient not at home today, could not take BP"

     #case/comment =
         "1 Mar 2017: Patient has high BP 145/90, should be monitored (chw1)"
         "10 Mar 2017: BP improved slightly 140/85, keep monitoring. (chw2)"
                  "14 Mar 2017: Patient not at home today, could not take BP (chw1)"

------------

Questions:
1) Is this possible? Can I just load current value of #case/comment from the patient case and use  concat() to create a new value to update it?

2) Is there a limit to the length of the text field (e.g. 255 chars) that I will run into?

3) Do you have a better suggestion for how I could implement this functionality?


Thanks!
Andrew