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!
@tomerg
http://il.linkedin.com/in/tomergabel
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