It might help you understand what's going on to bind the fn to a name and poke at it a bit: (let [by-five (fn [x] (* 5 x))] [(by-five 5) (by-five 6) (by-five 7)]) ;; => [25 30 35]
This results in a vector <http://clojure.org/data_structures#Data Structures-Vectors (IPersistentVector)> with the result of multiplying 5 by 5, 6, and 7 respectively. The let special form <http://clojure.org/special_forms#Special Forms--(let [bindings* ] exprs*)> allows you to bind values to names within the body of the let. You can see that "by-five" is in front of 5, 6, 7. That's because in Clojure (and Lisps in general) the first element of a list (parentheses) is viewed as a function to be invoked (in this case "by-five") and the rest of the list are the parameters to the function. This evaluates to the same as the let form: [((fn [x] (* 5 x)) 5) ((fn [x] (* 5 x)) 6) ((fn [x] (* 5 x)) 7)] ;; => [25 30 35] On Friday, January 2, 2015 8:13:41 PM UTC-5, novato wrote: > > I choose clojure as my first programming language after some research. I > am learning by doing Clojure Koans <http://clojurekoans.com/> exercises. > I reached to the functions "lesson" and I have a doubt on the following > code: > ((fn [x] (* 5 x)) 5) > > Why is that the last 5 is outside the fn parentheses? Why this doesn't > work? > (fn [x] (* 5 x) 5) > > Thanks in advice for the clarification and excuse my poor english. > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
