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![FUNCTIONAL
fac(N) when N == 0 -> 1;
fac(N) when N > 0 -> N*fac(N-1).
Recursion
double([H|T]) -> [2*H|double(T)];
double([]) -> [].
Pattern matching](https://image.slidesharecdn.com/whyerlang-140416132935-phpapp01/85/Why-erlang-25-320.jpg)
Uploaded byDoug Goldie
Why erlang
This document contains the agenda and notes from an Erlang meetup held on April 14, 2014 in Silicon Valley. The meetup included an introduction, discussions on why Erlang is useful, how WhatsApp uses Erlang, the origins and capabilities of Erlang, programming concepts in Erlang like concurrency and fault tolerance, and references for further information. The agenda included times for doors opening, introductions, presentations on why Erlang and how meetups are organized, an Erlang introduction, and doors closing.
Why erlang
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- 2. AGENDA 6:30 - Doorsopen 6:45 - Introduction / Announcements 7:00 - Why Erlang? 7:45 - Meetup Organization 8:15 - Erlang Intro 9:00 - Doors close
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- 4. DOUG GOLDIE Freelance developer,architect, consultant Ruby, Rails stack Boatbound, V.me at Visa, Paynearme doug@codecauldron.com
- 5. WHY ERLANG? by DougGoldie
- 6. WHATSAPP • 465M monthlyusers • 19B messages in & 40B out per day • Small team (~10 on Erlang), handle development and ops • ~ 550 servers + standby gear • > 11,000 cores
- 7. A YEAR AGO… •I took the summer off…. • “Why Erlang?” • Challenges of SOA • Curious about Erlang. • Learn a functional language again.
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- 9. TELECOM NEEDED • Concurrency •Distribution • Fault Tolerance • Soft real-time • Hot code upgrade • Incremental code loading • External interfaces
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- 11. CONCURRENCY • Isolated processes •Asynchronous messaging passing • Actor model
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- 18. Deadlines Soft allows someslip SOFT REAL-TIME Lightweight processes. Garbage collection
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- 23. –Robert Virding, OTPclass, 2014 “It’s about building Systems.”
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- 25. FUNCTIONAL fac(N) when N== 0 -> 1; fac(N) when N > 0 -> N*fac(N-1). Recursion double([H|T]) -> [2*H|double(T)]; double([]) -> []. Pattern matching
- 26. MODULES, ETC. • Modules •Behaviours
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- 28. OTP• Library ofDesign Patterns • Supervision Tree • Workers and supervisors • Behaviours
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- 32. ELIXIR • Jose Valim •Light layer of syntactic sugar • Pipes • Macros
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- 34. THE WEB • Concurrent •Soft real-time • Asynchronous • Omnipresent • Internet of Things
- 36. REFERENCES • Erlang andthe Web http://ninenines.eu/docs/en/cowboy/HEAD/guide/erlang_web/ • Concurrency Oriented Programming in Erlang http://www.guug.de/veranstaltungen/ffg2003/papers/ffg2003-armstrong.pdf • Why OO Sucks http://www.sics.se/~joe/bluetail/vol1/v1_oo.html • Erlang Central https://erlangcentral.org/ • Erlang History http://www.erlang.org/faq/academic.html • WhatsApp presentation http://www.erlang-factory.com/conference/show/conference-6/home/#rick-reed
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