Srihari Sriraman | nilenso | reClojure | December 2022 How to foster growth for beginners and intermediates? 
 How to enable success for Clojure in your company? Growing Clojure in the company 

• Been writing Clojure professionally for ~10y • Trained folks at nilenso, ran courses for clients • Taught at workshops, IN/clojure, clojure-bridge, etc • I like Clojure, and would love to see more of it around A little about me 

Agenda What are the challenges? Training beginners Supporting intermediates Enabling success 

What are the challenges? How is growing Clojure di f ferent from growing any other language? 1. Multi-paradigm-shi f t 2. Smaller user base 3. Hiring senior Clojurists 4. Fighting prejudices 

1. Multi-paradigm-shift • So many brackets! • Everything goes in the same line. • Where are my variables? • Give me a for-loop already. • What’s the Type of that argument again? • Argh a stack trace again; I don’t know Java! Lisp 
 [Structural editing, REPL] Functional 
 [Immutability, declarative, HOF] Dynamic [Error handling] Hosted / JVM } } 

• Search engine results aren’t the best • Not enough beginner friendly code examples • Idioms are not widely understood • Not many friends who can look over your shoulder 2. Smaller user base Th e problems of the community needn’t be the problems of your company. 

3. Hiring senior Clojure devs • Senior folks drive outcomes • Seniors are necessary to train beginners • Senior developers are expensive Growing senior devs is involved, but doable 

• I use the REPL, so I don't need tests • I REPL into production to hot fi x • I write integration tests, so I don't need to write unit tests • I can’t create a team of 100 Clojure developers • There are no types, so it won't work for large codebases Training has to be holistic, not just about the language 4. Fighting Prejudices 

Training beginners Bootcamp Guiding Principles Support 

• Duration: 1-3 months • Teacher:Student :: 1:4 • Active teaching:Pairing :: 25:75 • 25% of learning happens from peers • Batch vs Individual Planning a bootcamp Fund the bootcamp with your hiring budget 

Learning, and delivering have di f ferent goals. Do not plan to build something useful as an exercise. 

• Create incremental goals, and tight feedback loops around each stage. Pair program. • Train holistically to be a good developer at your company, don’t just teach the language Guiding principles 

• Focus on learning to use Clojure. Provide setup, plumbing, and library choices; these can be learnt later, or on the job. Guiding principles 

• Focus on learning to use Clojure. Provide setup, plumbing, and library choices; these can be learnt later, or on the job. • Put the learning in context by creating realistic exercises in the company’s domain. Use the same infrastructure, libraries and general setup as your regular projects. Guiding principles 

• Give ample time to get familiar with the philosophy of the language, the rationales, and principles behind language choices. • Focus on learning to use Clojure. Provide setup, plumbing, and library choices; these can be learnt later, or on the job. • Put the learning in context by creating realistic exercises in the company’s domain. Use the same infrastructure, libraries and general setup as your regular projects. Guiding principles • Get ample facetime with Rich Hickey • Give ample time to watch Rich Hickey videos 

Example course Clojure from the ground up 
 1 week 4clojure problems (~50 easy, medium, hard) 
 2 weeks Exercise: Mars Rover 
 1 week Exercise: Transform and load 
 2 weeks + structural editing + REPL work f low + idioms + tests + modelling / design + PRs + editor + REPL in editor + real domain + libraries + collaboration 

Providing support Setup [editor, REPL, deps] Automate Using the REPL Handhold, get it right Using clojure.core e f fectively 4Clojure + refer top solutions Learning idioms Let them watch you refactor Imperative thinking Discourage use of loop/recur, and reduce for 4Clojure problems 

Providing support Lack of variables Use `let`, then pair to refactor Aligning code Point to clojure-style-guide, or provide a customised formatter. Lack of a framework Use a fully featured template while learning Debugging Direct towards editor capabilities, and then towards support material 

Reading materials https://gist.github.com/ssrihari/0bf159a f b781eef7cc552a1a0b17786f 

Supporting Intermediates How to o f fer continual support a f ter the bootcamp? 
 Where do intermediates get stuck? 

1. Pairing 2. Watching you review / refactor 3. Reviewing PRs 4. Structured feedback at intervals Where do you find the time? Impact Asynchronous 

Beginner material is the foundation. Reinforce the fundamentals for lateral hires who need it. 

Where they need help • Debugging • Modelling • Organising code • Error handling • Schema / Spec • Design patterns • Concurrency design 

Reading materials https://gist.github.com/ssrihari/0bf159a f b781eef7cc552a1a0b17786f 

Enabling Success What new problems emerge as your team grows? 
 What are some factors that increase chances of success? 

Choosing Clojure is not a substitute for keeping it simple. 

a great responsibility is the inseparable result of a great power [src] + as your team grows, the responsibility grows 

• Convention over con fi guration. Choose the libraries you use as a company, and stick to them unless there’s a good reason to deviate. Create a template project. • Double down on tests. Guard PR merges from basic checks: tests, linting, coverage, etc. • Extract libraries from common code and schemas, and appoint maintainers for them • Write down guidelines on tricky topics like error handling and data validation. Building 

• Get to zero downtime deploys, do rolling deploys • Review basic JVM f lags, watch the GC spikes • Do not REPL into production unless absolutely required • Tighten API schemas, DB data types Shipping 

Success stories are inspiring. Showcase them. 

• Emphasise key levers • Time to production • Fewer lines of code • Expressive code • Play to Clojure's strengths • Data processing • Parallel processing • DSLs, immutable/temporal databases • Rule based systems Supporting success 

• Use success stories to recruit into your team • If you have the time, run bootcamps for interested groups • Multiply yourself • Record bootcamp, and refactoring videos • Encourage intermediates to own bootcamps • Have other people respond in #clojure-beginners Growing 

Srihari Sriraman | nilenso | reClojure | December 2022 Growing Clojure in the company