You always get functions handed to you in programming languages. CPU instructions are handed to you. Scheme, has a small core of special forms which are handed

You always get functions handed to you in programming languages. CPU instructions are handed to you. Scheme, has a small core of special forms which are handed to you. You build up bigger specific things from small general things. In factorio you create bigger functions from smaller ones as explained in the article in great detail. The routing and layout part is about organization, but the more abstract notions of combinations and ratios are "functional" in the sense of the article.