Upskilling newcomers in Clojure

Hiring someone with experience in a niche language like Clojure can be quite difficult. The alternative is to hire a good programmer and upskill them on the language and stack. The talk will delve into how this can be done well, and is based on our experience in doing this for many years at Nilenso.

Transcript

1. Upskilling Newcomers
   in Clojure
   Srihari Sriraman | nilenso
   

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2. Upskilling newcomers in Clojure
   1. Why I’m giving this talk
   
   
   2. What works for most people
   
   
   3. Time frame
   
   
   4. Training on the job
   
   
   5. Axes of learning Clojure
   
   
   • Dynamic
   
   
   • Functional
   
   
   • Lisp
   
   
   • JVM
   Agenda
   

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3. Upskilling newcomers in Clojure
   It is hard to
   fi
   nd and hire Clojure developers:
   
   
   • Relatively easier to train good developers in Clojure
   
   
   • Sharing experiences, and collating thoughts helps
   
   
   • Assuming there’s someone well versed in Clojure at the
   organisation
   Why I’m giving this talk
   A little about me:
   
   
   • Been writing Clojure professionally for ~8y
   
   
   • Trained folks at nilenso, ran courses for clients
   
   
   • Taught at workshops, in/clojure, clojure-bridge, etc
   

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4. Upskilling newcomers in Clojure
   • Learning to drive from the REPL is crucial. Go slow, and hand-hold the initial learning.
   
   
   • Pick a Clojure book: JoC, Clojure Programming, or Brave Clojure
   
   
   • 4clojure exercises, koans / katas
   
   
   • Write a few practice projects in Clojure: BST, mars-rover, crud app, auth
   
   
   • Continuous feedback: pairing roster, PR reviews
   
   
   • https://www.clojurenewbieguide.com/
   What works for most people
   

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5. Upskilling newcomers in Clojure
   •
   Th
   is obviously di
   f
   fers based on individuals, and the organisation
   
   
   • 2-3 months is what we’ve seen as a minimum at nilenso
   
   
   • 2 to 6 months to be fully independent in learning
   
   
   • Move learning to on-the-job depending on the job, and comfort
   
   
   • Suggestion: at least 1 month or so just learning Clojure if new to it
   Time Frame
   

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6. Upskilling newcomers in Clojure
   Functional Paradigm
   • Write code procedurally
   fi
   rst, shake o
   f
   f the OO patterns
   and abstraction muscle memories
   
   
   • Data
   f
   low programming, data oriented programming
   
   
   • How to use
   fi
   rst class functions well: middleware,
   functions in maps
   
   
   • Functions as the primary abstractions / building blocks
   Focus on learning
   Exercises
   Learning Materials
   New for people from strong OO backgrounds like
   Java, Ruby, C++, etc.
   • Write data pipelines: map,
   fi
   lter, reduce, etc
   
   
   • Re-solve problems solved in OO
   
   
   • Web scrapers, ETL pipelines, BST, mars-rover
   • FP for the Object Oriented Programmer
   
   
   • First chapters of JoC
   
   
   • When to use OO data structures in Clojure
   
   
   • SOLID in Clojure, Design Patterns in Clojure
   
   
   • Clojure for Java programmers
   

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7. Upskilling newcomers in Clojure
   Lisp
   •
   Th
   e REPL work
   f
   low, comfort in editor
   
   
   • Structural editing
   
   
   • Dig into clojure.core o
   f
   ten, macroexpand core
   
   
   • Organising code in namespaces
   Focus on learning
   Exercises
   Learning Materials
   Th
   is is new to most people, even seasoned FP folks,
   unless they come from a CL/Racket background.
   • Enforce using paredit for all s-exp editing
   
   
   • Write some syntax-sugar macros
   • Stu's Repl Drive Development talk
   
   
   • Cursive’s structural editing tutorial
   
   
   • Zach’s abstraction talk, Data > Functions > Macros
   
   
   • Tim Baldridge’s talk about core-async
   implementation
   

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8. Upskilling newcomers in Clojure
   JVM
   • Concurrency constructs in Clojure
   
   
   • Parallelism via java.util.concurrent
   
   
   • Interop with java
   
   
   • Pro
   fi
   ling tools
   
   
   • Object allocation on heap, and GC
   
   
   • Java ecosystem: builds, maven, popular libraries
   Focus on learning
   Exercises
   Learning Materials
   New to people without Java experience, and a
   critical learning area for operational e
   f
   fectiveness.
   • Create a wrapper library for a Java library
   
   
   • Reduce CPU usage by 10% by pro
   fi
   ling using visualvm
   
   
   • Create async workers using j.u.c/executors
   
   
   • Embed a Clojure program in a java codebase
   • Clojure for Lisp Programmers
   
   
   • Concurrency and parallelism
   
   
   • JoC chapters 4 & 5
   
   
   • Java concurrency in practice
   

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9. Upskilling newcomers in Clojure
   Dynamic
   • Clojure’s evaluation model
   
   
   • Domain modelling as maps, and reliance on names
   
   
   • Sequences and collection interfaces
   
   
   • Error, and exception handling
   
   
   • Spec, and schema are friends, but not pseudo types
   
   
   • Clojure’s approach towards identity, and state
   Focus on learning
   Learning Materials
   New for people from strong static typing
   backgrounds like Haskell, C/C++, Go.
   • Rich’s rationale around Clojure’s dynamism
   
   
   • Clojure vs the static typing world
   
   
   •
   Th
   e sequences part of Programming Clojure
   

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10. Upskilling newcomers in Clojure
    • Continuous feedback is key, strive to create feedback loops at micro and macro levels.
    
    
    • Pair programming, and shadowing if pairing is not practiced is a good idea
    
    
    • PR Reviews: give feedback on approach, responsibilities of the function
    
    
    • Mob reviews: give feedback on idioms, point to style guides, better core functions to use
    
    
    • Idioms can take time to learn
    Training on the job
    

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11. Upskilling newcomers in Clojure
    Thoughts? Questions?
    What was your experience learning Clojure?
    

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