I'm wandering about if there is anyway to add comments and explanation into actions and actions groups, to explain what the expression do (each line), this way it becomes easy to understand in posterior views. As I'm beginning with the regexp, this would help a lot...
Yes, use (?#)to sit beside the regexp with the comment between the #and ). See attached it working for and the same can be said for using it in the replace with regular expressions action.
As long as it doesn't break the functionality of the regexp it's fine. It makes sence to put the comment before the regexp. So an example for matching dates in the format YYYY-MM-DD your regexp would look something like this.
Begin Action Group _Script Test#TEST
Action #1Actiontype 5: Format valueField ______: YEARFormatstring: $regexp(%date%,'(?#DATE Format YYYY-MM-DD to YEAR in YYYY)(\d{4})-\d{2}-\d{2}','$1')