FP adoption at REAA 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

2013 2014 2015 2016 2017

Teams using Scala

2013 2014 2015 2016 2017

Scala codebases

100

0

50

17

17

38

91

Total codebases: ~5200~2% are Scala

Beyond Scala

Of 858 public channels:• #28 all-time messages• #28 total members• #32 users posting messages

Weekly FP Guild session

2013 2014 2015 2016 2017

0

50

10

1518

25Attendance/week

10

20

30

40

4

15 1417

…

Different presenters

YOW Lambda Jam 2017

C◦mp◦se :: Melbourne 2017

Human approach

SOFTWARE COMPANY

• Solve my problems• Help me do what I

do• On time• Supported

Customers

Real world Software

Customers

Users

SOFTWARE COMPANY

• Easy to use• Make my

life easier• Reliable

Customers

Users

Management

• Bottom line• Hiring?• Long term view• Org health• Manage risk

Customers

Users

Product Managers

• Verify assumptions• Features!• Time to market

Management

Customers

Users

Product ManagersManagement

• Sleep at night• Visibility• Uptime, security,

latency, performance, etc

Site Ops

Customers

Users

Product ManagersManagement

• Determinism• Reproducibility• Confidence

Site Ops

QAs

Customers

Users

Product ManagersManagement

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

QAs

Developers

YOW

Customers

Users

Product ManagersManagement

Site Ops

QAs

THE CODEDevelopers

YOW

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

YOW

The easy bit

YOW

THE HARD BIT

YOW Why bother?

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

programs• Better separation of

concerns

THE CODE

THE CODE

• Can actually know things about the code

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

Developers

YOW

THE CODEDevelopers

YOW

QAs

• Same input gives same response!

• We can reproduce things

THE CODEDevelopers

YOW

QAs

• Rarely fails, in well understood ways

• I can sleep

Site Ops

THE CODEDevelopers

YOW

QAs

• Devs could painlessly bolt my features on that old codebase!

• I don’t hear “no” as often

Site Ops

Product Managers

THE CODEDevelopers

YOW

QAs

Site Ops

Product ManagersManagement

• Great for hiring!• Vibrant, energetic

team• Microservices mitigate

risk in tech choice

THE CODEDevelopers

YOW

QAs

Site Ops

Product ManagersManagement

Customers / Users

• Reliable!• Regular

updates

Tech choices are important becausethey can make people’s lives better

YOW

YOW

YOW

Alan TuringTuring machines

Alonzo ChurchThe Lambda Calculus

Programming languages existed before computers did

Programs exist like numbers

exist!

Fundamental software principles

Applicability

VSLast week’s hot web framework

Every single dayEvery languageEvery problemEvery context

Next 6 months, if you’re lucky

Substance Eternal and unchanging fabric of the universe

Eternal hamster wheel of memorising steaming piles of human error

Long-term consequence

Happiness, productivity & wisdom

Quit and become a dentist like Mum always wanted

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

Phil Wadler

@

FP Guild, team dojos Chat channels

Shared norms Central expert group

#

shared normsiOS

shared norms

shared norms

shared norms

Weekly guild meetings

#functionalprogramming

Weekly guild meetings

#functionalprogramming#sig-scala

shared norms

shared norms

shared norms

advicecode reviewarticlessupport

secondmenttraining sessions

shared norms

shared norms

shared norms

Central expert group

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!

Maybe

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

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

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”

Case study 1: Colliding teams

Chalk Services Cheese Experience

Time for a re-org!

You are now the “Chalk & Cheese Dept”

Hi there! Welcome!

Hooray! Let’s get to work.

The hell am I even looking at

Seriously, I’ve been doing this for 10 years and now I

can’t do anything

Oops! Let’s scale it back a notch.

Cheers!

No worries! You’re doing great.

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.

We have to help our

teammates! I’ll make

tutorials…

I’ll run a weekly training session!

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?

Case study 2: Decay & drift

Time for something new! Let’s use Scala

Can you help us with some weekly training sessions?

Sure!

6 months later… turnover!

What do we do with this thing?

I never really wanted this tbh

Me neither

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!

Sure, I can fit you in

once/week!

Could you help us with some training?

It’s up to me to make sure my

teammates are having a good time with this

Let’s keep it simple…

Good idea!

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

val modifyBanana(b: Banana): Banana = ??? Oh man.

Struggling.Let’s slow down!

I’ll help out.

Weekly survey

How are you finding it?

1 5

etc

1 5

Can you use technique X in anger?

Let’s keep track of out progress, to work out how we’re doing!

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

Still struggling.

You’re doing great! We’ll all

help

6 months later… success!

Project was a success! Well done team!

We’re really happy with this

code!

We’ve levelled

up!

AntipatternsHow FP adoptions fail

Antipattern 1: Under the rug

I’m going to lose my

hipster badge at this rate

Haskell in prod,LIVING THE

DREAM BABY!!!

Where did this come from??

I never would have agreed to this!

It looks weird and we didn’t sign up for this

Antipattern 2: Wizard Tower

Profunctor optics! Church-encoded free

monad. Left Kanextension enriches our algebra into a

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

Tense, fragile situation…

Soon enough… Howdy folks I’m the new CTO!

I’m really excited to….GOOD LORD what

is going on there

You hear something? Nope.

Antipattern 3: Flock of seagulls

Can you folk help us out? AgileConsultyCorp

Sure can!

This will never do!

Let’s add some AgileConsultyCorp

pizzazz!

FP Guild

Every Wednesday 4pm without fail

f ◦ (g ◦ h) = (f ◦ g) ◦ h

2014

f ◦ (g ◦ h) = (f ◦ g) ◦ h

4x

2015

(theory)

f ◦ (g ◦ h) = (f ◦ g) ◦ h

15x

(12x first time speakers)

2016

(theory)f ◦ (g ◦ h) = (f ◦ g) ◦ h

14x

(6x first time speakers)

2017

f ◦ (g ◦ h) = (f ◦ g) ◦ h

(theory)17x

(7x first time speakers)

Low bar

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

Consistency

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

- Lorne Michaels, SNL creator

Consistency

• Consistency is really important for building confidence in a group

• Every Wednesday 4pm without fail, 4 years running

• (except for Christmas & Hackathons)

Consistency

1. Call for talks on Monday2. Pester individuals 3. Riff on something off the top of head4. Watch video

Fallbacks:

Variety

Same thing…

Variety

Same thing…

Variety

Same thing…

Variety

Same thing…

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

Look after beginners and the experts will look after themselves

Blah blah monad stack, typeclass coherence

I’ll bet I’m the only person who

doesn’t understand this

Imagined:

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

• Natural bias toward advanced talks• Encourage beginner talks• Encourage beginners talking!• Bigger, more diverse crowds

• 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