erlang_tech_night

agenda

Cyryl

• Erlang the movie

• history of Erlang

• why the need for another language

• thinking functional

• benefits of knowing functional language for OOP programmers

• sample OOP program

Fabian

• rewriting OOP example in Erlang
• Q&A

slides

http://wroclaw.erlangers.org/erlang_tech_night

the movie

google + erlang the movie

demo

.net

use --path=../../../../data for launch from debug

demo program:

1. get directory as parameter
2. for each file in the directory: 2.1 split into words 2.2 count words
3. display count per file

reference output:

C:\Users\cplotnicki\dev\erlang_tech_night\data\1ws4910.txt: 18368

...

C:\Users\cplotnicki\dev\erlang_tech_night\data\nkrnn11.txt: 371870

all words in all files: 4740653

erlang

$ cd example/erlang/

console #1

$ git checkout <milestone-sha1> -- word_count.erl

console #2

$ erl
Erlang R15B01 (erts-5.9.1) [source] [smp:4:4] [async-threads:0] [hipe] [kernel-poll:false]

Eshell V5.9.1  (abort with ^G)
1> c(word_count). % after each milestone
{ok,word_count}
2> word_count:start(). % except #1 and #2
...

milestones

1. acbed19a91dee10c1cea96c3db9f213dc42f1302 empty module example
2. 287999f941c405442a0e2fe58bedc4c15ba1c307 list data dir
3. ba1ec3912c3afe3b23a98498cc140d4d862703bd print lines + exception
4. b5726365630e4ad9b2f0fcb57b9c382a60ba54cf proper eof handling
5. df9282c164f5a9157ce242e2f8e4a41118be9053 count words for each line
6. 51dd3682a0094ce80672624d641931a4ff5878ac sum
7. 6c88cdf951013159e6be24badcd36ef4d3060cb2 run on all files + sum
8. 1145054318d0385674603b1093c72c93c1c92070 prepare for processes
9. 78a74306b141214eb0c884f3f3b144aeccde18ec processes!!!!