nip2 includes a tiny lazy functional programming language. You can use it to glue VIPS image processing functions together to perform more complicated tasks. All of the nip2 toolkit menus are written in this language.
These first sections just describe the programming language. See §4.4 for a description of the programming window. You use nip2’s programming language to control the user interface: the link between what happens inside a nip2 function and what you see on the screen in covered in §6.12.