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
   

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5. ?
   

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7. ?
   

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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
   

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10. https://re-find.it
    

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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)
    

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12. Why not just try everything
    without using spec?
    

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13. Why use spec for this?
    Recommend only idiomatic functions

    

    

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14. Spec validation
    (s/fdef clojure.core/inc
    :args (s/cat :x number?)
    :ret number?)
    {:args [1]

    :ret 1}
    

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15. Spec validation
    (s/fdef clojure.core/inc
    :args (s/cat :x number?)
    :ret number?)
    

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16. Spec validation
    (s/fdef clojure.core/inc
    :args (s/cat :x number?)
    :ret number?)
    But (inc 1) is not equal to 1...
    

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17. Spec validation
    (s/fdef clojure.core//
    :args (s/cat :numerator number?
    :denominators (s/* number?))
    :ret number?)
    (= 1 (/ 1 1)) ;; true
    

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18. spec + exact
    match
    

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19. spec + type
    match
    

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20. permutation of
    args
    

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21. Finitize
    

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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
    

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23. web + lib/CLI + JavaFX
    

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24. Thank you!
    Questions or suggestions?

    @borkdude
    

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