Click on Yes when asked to edit the source. A new VHDL editor window opens up for the latch8 module. Creating the latch8 entity 1. Try to follow the code and understand how it works. In order to manage large projects, the language was defined around the notion of libraries.
Every library is a level of abstraction for a specific kind of code.
You can see that the first 3 lines in our latch8 are exposing and using the IEEE standard logic libraries. As Libraries are an abstract object, it is essential for us to instruct the compiler to look for them in its physical file domain. Every VHDL compiler designer solves this problem in a different way. A special case is the work library. The compiler treats the work library as the current working area in which all the design hierarchy entities reside.