How to convert PHP Logic to Views API
There is some discussion in several places about this, including an issue in the Composed Field issues queue. 

The module author writes;


  I haven't investigated the mechanics behind it but theoretically all that needs to be done is to somehow implements the process that those modules do on retrieving the field value from the database and then unserialize and concatenate the retrieved value.


The problem of course with storing serialised data is the inability to effectively query it using any type of relational db (No indexes.) 

You can always build a query using a LIKE on the serialised data ... 

WHERE field_one-composed LIKE '%query%'; 


But that's horrible. :( 

My comment on the initial question stands; do you want to achieve this using the GUI or through code? I'll update this answer based on your response.

While I appreciate this is not the question, I'm curious about why you chose this module for your use case?