For one of my projects I needed an interactive console command in Yii 1, i.e. the one that is gathering all information from user in an interactive mode (a serie of questions and answers displayed directly in the console), ignoring command-line arguments at all.
I have been working on a REST API using the excellent tools provided by Yii2. My problem was that I have to differentiate between empty values and null values. In other words, <elem></elem> is different from null as it represents an empty string. Also, although some use <elem/> to represent a null value it should still be interpreted as an empty string. In other cases, the absence of the element is taken to represent a null value, but this may create problem with some parsers.