1. A computer storage medium having computer-executable instructions, which when executed perform actions, comprising: obtaining a first computer code encoded in a first computer programming language, the first computer code being derived from a second computer code encoded in a second computer language; via a user interface, receiving changes to the first computer code; and creating a delta that indicates changes to make to the second computer code to obtain a third computer code, the third computer code corresponding to computer code that would be generated by translating the first computer code as updated with the changes into the second computer language.