Re-find: discover functions with spec

Re-find is an app and a library that lets you interactively discover Clojure functions based on example in- and output values or predicates. In this talk we will see how it works and how it is implemented, using clojure.spec as the driving force.

About the speaker: Michiel Borkent is a software developer and Clojurian. He can be found as @borkdude in various places on the web.

This presentation was given at Dutch Clojure Days 2019:

https://clojuredays.org/#Re-find:%20discover%20functions%20with%20spec

Transcript

1. re-find Michiel Borkent
 @borkdude
 Dutch Clojure Days 2019-04-06 discover functions with spec
5. ?
7. ?
9. rationale for re-find • You are learning Clojure and don't know the names or even the existence of functions • You know a function exists, but forgot the order of arguments it takes
10. https://re-find.it
11. How does it work? • re-find searches within spec’ed functions • so it needs a collection of specs (speculative, but could be other specs for core or self-defined functions)
12. Why not just try everything without using spec?
13. Why use spec for this? Recommend only idiomatic functions
 

14. Spec validation (s/fdef clojure.core/inc :args (s/cat :x number?) :ret number?) {:args [1]
 :ret 1}
15. Spec validation (s/fdef clojure.core/inc :args (s/cat :x number?) :ret number?)
16. Spec validation (s/fdef clojure.core/inc :args (s/cat :x number?) :ret number?) But (inc 1) is not equal to 1...
17. Spec validation (s/fdef clojure.core// :args (s/cat :numerator number? :denominators (s/* number?)) :ret number?) (= 1 (/ 1 1)) ;; true
18. spec + exact match
19. spec + type match
20. permutation of args
21. Finitize
22. Stack • Self-hosted CLJS • Low operational cost (just static HTML + JS) • No security risks (evaluation on server) • CodeMirror + parinfer layer • automatic paren matching, closing, highlighting • CLJC: re-find lib works in Clojure and (self-hosted) CLJS
23. web + lib/CLI + JavaFX
24. Thank you! Questions or suggestions?
 @borkdude