functional leap of faith (keynote at jday lviv 2014)

Functional Leap of Faith

Tomer Gabel, WixJDay Lviv 2014

Through the Looking Glass

20 years ago…

• C/C++ rule the

market [1]

• First release of

Java

[1] TIOBE Index (historical data)

… since then?*

• C and Java are neck-and-neck• Virtual machines are everywhere• Garbage collection is everywhere• OOP is everywhere

* Not exhaustive

Virtual Machines

1967 BCPL

1978 UCSD p-System

1994 JVM

2014 Everywhere!

Garbage Collection

1960 Formalized[1]

1970s Research

1994 JVM

2014 Everywhere!

[1] Recursive Functions of Symbolic Expressions and Their Computation by Machine, Part I

Object-Oriented Programming

1967 Simula 67

1980 Smalltalk 80

1983 C++

2014 Everywhere!

Advances take decades to become mainstream

Market Growth[1]

1975 1980 1985 1990 1995 2000 2005 2010 2015* 2020*0

500000000

1000000000

1500000000

2000000000

2500000000

3000000000

[1] eTForecasts Worldwide PC Market Research Report

1975 1980 1985 1990 1995 2000 2005 2010 2015* 2020*0

500000000

1000000000

1500000000

2000000000

2500000000

3000000000

Market Growth

• Structured Programming

• Module Systems

• Dynamic Memory

Allocation

1975 1980 1985 1990 1995 2000 2005 2010 2015* 2020*0

500000000

1000000000

1500000000

2000000000

2500000000

3000000000

Market Growth

• Garbage Collection

• OOP

• VMs and JIT

1975 1980 1985 1990 1995 2000 2005 2010 2015* 2020*0

500000000

1000000000

1500000000

2000000000

2500000000

3000000000

Market Growth

You are here!

What’s holding us back?

The Market has Shifted

• SaaS is the norm

• Shorter time to market

• Latency requirements are stricter

• Availability is business-critical

The Free Lunch is Over[1]

[1] The Free Lunch is Over, Herb Stutter (Dr. Dobb's Journal, 2005)

• CPUs aren’t getting (much) faster

• Rather, they’re getting parallel

• Concurrency is the new kid on the block

Datasets are Getting Bigger

• Terabyte-scale data is common

• Computation demand – NoSQL– Big Data

• Specialized hardware (SAN) is a hindrance

We need new abstractions.

Three desirable attributes:

Today’s systems

are highly available & reliable.

Tomorrow’s abstraction must…

encourage correct code.

Complexity is the Mind Killer

• Complex system bigger

codebase

• More code more bugs

• We want less code

• We want correct code

Control flow Data flow

We need to invert our thinking.

How What

We need to invert our thinking.

Control flow describes the how

List<Person> adults(List<Person> in) {

ArrayList<Person> out = new ArrayList<>();

for (Person p : in) if (p.getAge() >= 18) out.add(p);

return out;}

Data flow describes the what

List<Person> adults(List<Person> in) { return in.stream() .filter(p -> p.age >= 18) .collect(Collectors.toList());}

“What” is Better

• Focuses on the problem

• Reduces accidental complexity

• Decouples intent from execution

I WANT YOU

TO STOPWORRYING

ABOUT TRIVIA

Today’s systems

are highly concurrent.

Tomorrow’s abstraction must…

encourage immutability.

The Case for Immutability

• Inherently thread-safe

• Referentially transparent

• Easier to reason about!

Today’s systems

are horizontally scalable.

Tomorrow’s abstraction must…

simplify workload distribution.

Distribution 101

1. Take a core computation

2. Split it out

3. Run on many nodes

4. Profit

Why is this hard?

• Behavior-as-data

• Side effects

• High-performance

frameworks

Lambdas

Immutability

Akka, Hadoop,

Storm…

The future is functional.

1. Data flow-oriented

2. Immutable3. Easy to

distribute

THANK YOU FOR YOUR TIME!

tomer@tomergabel.com

@tomerg

http://il.linkedin.com/in/tomergabel