Triskelion and Crapshoot

Triskelionand

CrapshootMiami Ruby Brigade

January 17, 2010

Monday, January 17, 2011

Triskelion and Crapshoot

•Triskelion - Rails application

•UI Elements

•Crapshoot - Dice-rolling library

•Parsing with Ragel

•Infix and Postfix Notation

•Random numbers


Pen and Paper Games

PensPaperDiceBooks

TalkingSnacks


Pen and Paper Games

PensPaperDiceBooks

TalkingSnacks




Timesta

mp


Timesta

mp

Name


Timesta

mp

Name

Tripcode


Timesta

mp

Name

Tripcode

Content


Colored NameEasier to read than text-only nickname

Shift the first few bytes of hash into LSBs of color

def chat_color digest = Digest::SHA1.hexdigest(self.tripcode + self.name) r = (digest[0..1].to_i(16) >> 1) + 127 g = (digest[2..3].to_i(16) >> 1) + 127 b = (digest[4..5].to_i(16) >> 1) + 127 "##{r.to_s 16}#{g.to_s 16}#{b.to_s 16}" end


Tripcode

Identity without Password or Registration

Used on 4chan

def tripcode_digest [Digest::SHA1.digest(self.tripcode)]. pack('m'). tr('+/','-_')[0..7] end


Chat

auto_link chat.content, :html=>{:target=>'_blank'}


Chat

auto_link chat.content, :html=>{:target=>'_blank'}

http://www.flickr.com/photos/lostvegas/2214183472/




Roll

 <%=h roll.code %> <%=h roll.result %> <%=h roll.description %>

4d6v + 40 =57 ((3+5+6+6-3)+40)




•UI Elements




•Random numbers


Dice Code

•2d4

•Two four-sided dice

•1d100 + 8

•One hundred-sided die plus eight

•4d6v

•Four six-sided dice, minus the lowest


Dice Language

A programming language is […] designed to express computations, […] to express algorithms precisely, or as a mode of human communication.

http://en.wikipedia.org/wiki/Programming_language


http://en.wikipedia.org/wiki/Computation

http://en.wikipedia.org/wiki/Computation

http://en.wikipedia.org/wiki/Algorithm

http://en.wikipedia.org/wiki/Algorithm





•UI Elements




•Random numbers


Regular LanguageIn computer science, a regular language is a formal language […] that satisfies the following equivalent properties:

•it can be accepted by a deterministic finite state machine

•it can be generated by a regular grammarhttp://en.wikipedia.org/wiki/Regular_language


http://en.wikipedia.org/wiki/Theoretical_computer_science

http://en.wikipedia.org/wiki/Theoretical_computer_science

http://en.wikipedia.org/wiki/Formal_language




http://en.wikipedia.org/wiki/Deterministic_finite_state_machine




Dice Language

4d6v 3d10^ 2d6 300+ – -


Dice Language

4d6v 3d10^ 2d6 300+ – -Expression


Dice Language

4d6v 3d10^ 2d6 300+ – -


Dice Language

2d6 300-


Dice Language

2d6 300-BinaryExpression


Dice Language

2d6 300-


Dice Language

2d6

300

-


Dice Language

2d6

300

-

Series


Dice Language

2d6

300

-

Series

Arithmetic


Dice Language

2d6

300

-

Series

Arithmetic

Constant


Dice Language

2d6

300

-


Dice Language

Number = digit+;

Constant = Number;

Drop = ('^' | 'v');Series = Number 'd' Number Drop?;

Arithmetic = ('+' | '-');

UnaryExpression = Series | Constant;BinaryExpression = UnaryExpression (space* Arithmetic space* UnaryExpression)+;Expression = UnaryExpression | BinaryExpression;

100%

CERTIFIED

REGULAR

LANGUAGE


Ragel

Ragel compiles executable finite state machines from regular languages. Ragel targets C, C++, Objective-C, D, Java and Ruby.

http://www.complang.org/ragel/




scan.rl%%{

machine scanner;

action _number { @mark_num = p } action number { @num_stack.push atos(data[@mark_num..p-1]) }

action constant { @tokens << Tokens::Constant.new(@num_stack.pop) } action series { drop = @drop_current @drop_current = nil sides = @num_stack.pop count = @num_stack.pop @tokens << Tokens::Series.new(count, sides, drop) } action arithmetic { @tokens << Tokens::Arithmetic.new(data[p-1].chr) }

action drop { @drop_current = data[p-1].chr }

Number = digit+ >_number %number;

Constant = Number %constant;

Drop = ('^' | 'v') %drop; Series = Number 'd' Number Drop? %series;

Arithmetic = ('+' | '-') %arithmetic;

UnaryExpression = Series | Constant; BinaryExpression = UnaryExpression (space* Arithmetic space* UnaryExpression)+; Expression = UnaryExpression | BinaryExpression;

main := Expression;}%%

Act

ions

Lang

uage


Ragel


Ragelscan.rl: 62 lines



scan.rb: 330 lines



scan.rb: 330 lines

scan.pdf: priceless


scan.rl

action constant { @tokens << Tokens::Constant.new(@num_stack.pop) } action series { drop = @drop_current @drop_current = nil sides = @num_stack.pop count = @num_stack.pop @tokens << Tokens::Series.new(count, sides, drop) } action arithmetic { @tokens << Tokens::Arithmetic.new(data[p-1].chr) }

Transform constant, series, and arithmetic elements into Token objects


Tokens

Token#eval Turn token into result during evaluation

Token#independentDetermine if token needs the next token during postfixing

Token#inspect<Crapshoot::Tokens::Series dice=4d6 drop=nothing>


Parsed Dice

4d6vcount: 4sides: 6drop: ‘v’

3d10^count: 3sides: 10drop: ‘^’

2d6count: 2sides: 6drop: nil

300value: 300

+ - -




•UI Elements




•Random numbers


Infix & Postfix


Infix & Postfix

Infix1 + 2 + 3 + 4

Used for centuries

Hard for computers


Infix & Postfix

Infix1 + 2 + 3 + 4

Used for centuries

Hard for computers

Postfix1 2 + 3 + 4 +

Easy for computers

Convertible from infix


Parsed Dice




300value: 300

+ - -


Postfixed Dice




300value: 300

+ - -


Postfix Evaluation


Postfix Evaluation

•Series


Postfix Evaluation

•Series

•Roll dice


Postfix Evaluation

•Series

•Roll dice

•Do drop


Postfix Evaluation

•Series

•Roll dice

•Do drop

•Push result to stack


Postfix Evaluation

•Series

•Roll dice

•Do drop


•Constant


Postfix Evaluation

•Series

•Roll dice

•Do drop


•Constant

•Push value to stack


Postfix Evaluation

•Series

•Roll dice

•Do drop


•Constant


•Arithmetic


Postfix Evaluation

•Series

•Roll dice

•Do drop


•Constant


•Arithmetic

•Pop twice


Postfix Evaluation

•Series

•Roll dice

•Do drop


•Constant


•Arithmetic

•Pop twice

•Push result


Postfix Evaluation




300value: 300

+ - -

Stack


Postfix Evaluation

15 3d10^count: 3sides: 10drop: ‘^’


300value: 300

+ - -

Stack


Postfix Evaluation

15



300value: 300

+ - -

Stack


Postfix Evaluation

15

5 2d6count: 2sides: 6drop: nil

300value: 300

+ - -

Stack


Postfix Evaluation

15 5


300value: 300

+ - -

Stack


Postfix Evaluation

15 5


300value: 300

+

- -

Stack


Postfix Evaluation

20


300value: 300

- -

Stack


Postfix Evaluation

20

9 300value: 300

- -

Stack


Postfix Evaluation

20 9

300value: 300

- -

Stack


Postfix Evaluation

20 9

300value: 300

-

-

Stack


Postfix Evaluation

11

300value: 300

-

Stack


Postfix Evaluation

11

300 -

Stack


Postfix Evaluation

11 300

-

Stack


Postfix Evaluation

11 300-Stack


Postfix Evaluation

-289Stack


Result

-289




•UI Elements




•Random numbers


Randomness

Computers are deterministic

Gather and store entropy where possible

Use secure hashes to disburse entropy


Randomness

Just use OpenSSL


SecureRandom

Ruby 1.9 and ActiveSupport

random_number

random_bytes

hex




•UI Elements




•Random numbers

Triskelion and Crapshoot

Technology

dice languagenumber

dice language4d6v 3d10

unaryexpression space

unaryexpression expression

unaryexpression binaryexpress

link chat

arithmetic space

regular grammarhttp