FP adoption at REA A human-first approach @KenScambler 11 Major - - PowerPoint PPT Presentation

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FP adoption at REA A human-first approach @KenScambler 11 Major - - PowerPoint PPT Presentation

Apr 18, 2023 400 likes •1.58k views

FP adoption at REA A human-first approach @KenScambler 11 Major companies using FP FP journey ~150 developers in Melbourne ~100 TW consultants in China ~90 in Malaysia Handful in Singapore, Thailand, Indonesia Teams using

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FP adoption at REA

A human-first approach

@KenScambler

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11

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Major companies using FP

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FP journey

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  • ~150 developers in Melbourne
  • ~100 TW consultants in China
  • ~90 in Malaysia
  • Handful in Singapore, Thailand,

Indonesia

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2013 2014 2015 2016 2017

Teams using Scala

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2013 2014 2015 2016 2017

Scala codebases

100 50 1 7 17 38 91

Total codebases: ~5200 ~2% are Scala

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Beyond Scala

Of 858 public channels:

  • #28 all-time messages
  • #28 total members
  • #32 users posting messages
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Weekly FP Guild session

2013 2014 2015 2016 2017 50 10 15 18 25 Attendance/week 10 20 30 40 4 15 14 17 … Different presenters

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YOW Lambda Jam 2017 C◦mp◦se :: Melbourne 2017

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Human approach

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SOFTWARE COMPANY

  • Solve my problems
  • Help me do what I

do

  • On time
  • Supported

Customers

Real world Software

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Customers Users

SOFTWARE COMPANY

  • Easy to use
  • Make my

life easier

  • Reliable
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Customers Users Management

  • Bottom line
  • Hiring?
  • Long term view
  • Org health
  • Manage risk
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Customers Users Product Managers

  • Verify assumptions
  • Features!
  • Time to market

Management

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Customers Users Product Managers Management

  • Sleep at night
  • Visibility
  • Uptime, security,

latency, performance, etc Site Ops

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Customers Users Product Managers Management

  • Determinism
  • Reproducibility
  • Confidence

Site Ops QAs

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Customers Users Product Managers Management

  • Do great work
  • Solve problems
  • Feel productive
  • Learn!

Site Ops QAs Developers

YOW

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Customers Users Product Managers Management Site Ops QAs

THE CODE

Developers

YOW

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Tech is ok, but nothing makes sense unless it makes people’s lives better

YOW

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The easy bit

YOW

THE HARD BIT

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YOW

Why bother?

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  • Input  Output
  • Less moving parts
  • Less coupling
  • Fewer possible incorrect

programs

  • Better separation of

concerns

THE CODE

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THE CODE

  • Can actually know things

about the code

  • Refactoring is easier!
  • Great code reuse
  • I’m learning!

Developers

YOW

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THE CODE

Developers

YOW

QAs

  • Same input gives

same response!

  • We can reproduce

things

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THE CODE

Developers

YOW

QAs

  • Rarely fails, in well

understood ways

  • I can sleep

Site Ops

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THE CODE

Developers

YOW

QAs

  • Devs could

painlessly bolt my features on that old codebase!

  • I don’t hear “no” as
  • ften

Site Ops Product Managers

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THE CODE

Developers

YOW

QAs Site Ops Product Managers Management

  • Great for hiring!
  • Vibrant, energetic

team

  • Microservices mitigate

risk in tech choice

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THE CODE

Developers

YOW

QAs Site Ops Product Managers Management Customers / Users

  • Reliable!
  • Regular

updates

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Tech choices are important because they can make people’s lives better

YOW

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YOW

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YOW

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Alan Turing Turing machines Alonzo Church The Lambda Calculus

Programming languages existed before computers did

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Programs exist like numbers exist!

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Fundamental software principles

Applicability VS

Last week’s hot web framework

Every single day Every language Every problem Every context Next 6 months, if you’re lucky Substance Eternal and unchanging fabric of the universe Eternal hamster wheel of memorising steaming piles

  • f human error

Long-term consequence Happiness, productivity & wisdom Quit and become a dentist like Mum always wanted

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...It would be a mistake to characterize lambda calculus as a universal language, because calling it universal is too limiting.

Phil Wadler

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@

FP Guild, team dojos Chat channels Shared norms Central expert group

#

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shared norms iOS shared norms shared norms shared norms Weekly guild meetings #functionalprogramming

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Weekly guild meetings #functionalprogramming #sig-scala shared norms shared norms shared norms

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advice code review articles support secondment training sessions shared norms shared norms shared norms

Central expert group

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Should my team use Scala?

Hey do you mind helping out with some advice for my team? We’re thinking about using Scala for the new service… Sure!

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Maybe

We’ve got a couple of Scala devs, and the rest

  • f the team is keen.

We want more maintainable assets. I can pay for an up-front learning curve.

  • Maybe. Here’s

some options, tradeoffs etc...

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We have tight deadlines, a new team of junior Ruby programmers, multiple stakeholders, and half our team is in Xi’an. I heard Scala will make us more productive. How can I make them like it?

ABSOLUTELY NOT

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Good signs Bad signs

  • Stable, established team
  • Existing FP/Scala experience
  • Project can bear learning curve
  • Good sentiment
  • Local developers
  • Realistic expectations
  • Unstable team
  • Nobody knows Scala/FP
  • Very tight deadlines
  • Mixed or negative sentiment
  • Offshore developers
  • “It’s the cool new thing”
  • “We’ll be immediately more

productive”

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Case study 1: Colliding teams

Chalk Services Cheese Experience

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Time for a re-org! You are now the “Chalk & Cheese Dept”

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Hi there! Welcome! Hooray! Let’s get to work.

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The hell am I even looking at

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Seriously, I’ve been doing this for 10 years and now I can’t do anything

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Oops! Let’s scale it back a notch.

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Cheers! No worries! You’re doing great.

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6 months later…

  • Oof. This is all

going a bit slower than we thought… Not going to lie, this Scala/FP stuff is tough

Is this really the right approach for us? Hmmm.

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We have to help our teammates! I’ll make tutorials… I’ll run a weekly training session!

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6 months later… Success!

Woohoo! Productivity! This software is rock solid! Love it! Devs are knocking down the door to join. Great results. Future though?

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Case study 2: Decay & drift

Time for something new! Let’s use Scala

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Can you help us with some weekly training sessions? Sure!

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6 months later… turnover!

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What do we do with this thing?

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I never really wanted this tbh Me neither

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Case study 3: Empathy FTW

?

We do a lot of maintenance, quality matters. A lot of our stuff is already Scala. We really want to learn. I’m happy to invest in our skills!

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Sure, I can fit you in

  • nce/week!

Could you help us with some training?

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It’s up to me to make sure my teammates are having a good time with this

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Let’s keep it simple… Good idea!

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val modifyBanana(b: Banana): Banana = ???

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val modifyBanana(b: Banana): Banana = ???

Oh man. Struggling. Let’s slow down! I’ll help out.

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Weekly survey How are you finding it? 1 5 etc 1 5 Can you use technique X in anger?

Let’s keep track of

  • ut progress, to

work out how we’re doing!

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val modifyBanana(b: Banana): Banana = ???

Still struggling. You’re doing great! We’ll all help

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6 months later… success!

Project was a success! Well done team! We’re really happy with this code! We’ve levelled up!

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Antipatterns

How FP adoptions fail

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Antipattern 1: Under the rug

I’m going to lose my hipster badge at this rate

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Haskell in prod, LIVING THE DREAM BABY!!!

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Where did this come from?? I never would have agreed to this! It looks weird and we didn’t sign up for this

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Antipattern 2: Wizard Tower

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Profunctor optics! Church-encoded free

  • monad. Left Kan

extension enriches

  • ur algebra into a

functor…..etc Why on earth would we care about all that?

Tense, fragile situation…

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Soon enough… Howdy folks I’m the new CTO! I’m really excited to….GOOD LORD what is going on there

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You hear something? Nope.

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Antipattern 3: Flock of seagulls

Can you folk help us out? AgileConsultyCorp Sure can!

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This will never do! Let’s add some AgileConsultyCorp pizzazz!

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FP Guild

Every Wednesday 4pm without fail

f ◦ (g ◦ h) = (f ◦ g) ◦ h

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2014

f ◦ (g ◦ h) = (f ◦ g) ◦ h

4x

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2015

(theory)

f ◦ (g ◦ h) = (f ◦ g) ◦ h

15x

(12x first time speakers)

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2016

(theory)

f ◦ (g ◦ h) = (f ◦ g) ◦ h

14x

(6x first time speakers)

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2017

f ◦ (g ◦ h) = (f ◦ g) ◦ h

(theory) 17x

(7x first time speakers)

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Low bar

  • Timebox to 2 hours prep, max
  • Lower bar means more speakers
  • More diverse speakers
  • Sanity for organisers
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Consistency

“The show doesn’t go on because it’s ready; it goes on because it’s 11:30.”

  • Lorne Michaels, SNL creator
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Consistency

  • Consistency is really important for building

confidence in a group

  • Every Wednesday 4pm without fail, 4 years

running

  • (except for Christmas & Hackathons)
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Consistency

  • 1. Call for talks on Monday
  • 2. Pester individuals
  • 3. Riff on something off the top of head
  • 4. Watch video

Fallbacks:

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Variety

Same thing…

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Variety

Same thing…

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Variety

Same thing…

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Variety

Same thing…

Week-to-week variety in speakers & topics is important!

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Look after beginners and the experts will look after themselves

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Blah blah monad stack, typeclass coherence I’ll bet I’m the only person who doesn’t understand this

Imagined:

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Blah blah monad stack, typeclass coherence I’ll bet I’m the only person who doesn’t understand this

Actual:

I’ll bet I’m the only person who doesn’t understand this I’ll bet I’m the only person who doesn’t understand this I’ll bet I’m the only person who doesn’t understand this I’ll bet I’m the only person who doesn’t understand this

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  • Natural bias toward advanced talks
  • Encourage beginner talks
  • Encourage beginners talking!
  • Bigger, more diverse crowds
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  • Functional programming is totally awesome
  • Technical benefits are worth pursuing
  • None of it matters a damn unless you can make it help people
  • By taking a human-first approach, a sustainable, self-perpetuating

culture of learning and achievement is possible, to everyone’s benefit

Conclusion