This isn't entirely true, you could compress the source code which would generate a dictionary (vocabulary) which could be used with the description (compressed

This isn't entirely true, you could compress the source code which would generate a dictionary (vocabulary) which could be used with the description (compressed output) to recreate the source code. You see comp sci is so advanced we don't even bother writing descriptions of our creations, we allow the software we've written previously create those descriptions for us, along with the dictionary used to understand the description, and then use another program to understand that description for us.