The Ruby Language [@+]pragdave dave@pragprog.com Ruby A tool for - - PowerPoint PPT Presentation

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The Ruby Language [@+]pragdave dave@pragprog.com Ruby A tool for - - PowerPoint PPT Presentation

Aug 14, 2023 122 likes •679 views

The Ruby Language [@+]pragdave dave@pragprog.com Ruby A tool for communication A tool for exploration A notation (like mathematics) 3 Ken Iverson Creator of APL (1962) 1979 Turing Award Winner 4 APL Sum first 5

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The Ruby Language

[@+]pragdave dave@pragprog.com

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Ruby

  • A tool for communication
  • A tool for exploration
  • A notation (like mathematics)
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  • Creator of APL (1962)
  • 1979 Turing Award Winner
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Ken Iverson

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  • Sum first 5 numbers:

+/⍳5

  • Prime numbers from 1 to R:

(~R∊R∘.×R)/R←1⍳R

  • Game of Life:

life←{↑1 ⍵.∧3 4=+/,¯1 0 1∘.⊖¯1 0 1∘.⌽⊂⍵}

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APL

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  • Creator of APL (1962)
  • 1979 Turing Award

Winner

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Ken Iverson

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  • Ease of expressing constructs arising in

problems.

  • Suggestivity.
  • Ability to subordinate detail.
  • Economy.
  • Amenability to formal proofs.

Good Notation

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  • Code close to the problem.
  • Help you discover new insights.
  • Build layers of abstraction.
  • Small set of basic concepts.
  • Amenability to formal proofs.

Good Notation

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  • Code close to the problem.
  • Help you discover new insights.
  • Build layers of abstraction.
  • Small set of basic concepts.
  • Easy to prove code correct.

Ruby

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  • Code close to the problem.
  • Help you discover new insights.
  • Build layers of abstraction.
  • Small set of basic concepts.
  • Easy to make code correct.

Ruby

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Ruby and Language

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The limits of my language are the limits of my world

Ludwig Wittgenstein—Logico-Tractatus Philosophicus 12
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The limits of my language are the limits of my world

Words? Idioms

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  • Words that combine to have special

meaning

  • Meaning shared between speaker and

listener

Idiom

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“Yoshi kicked the bucket”

Idiom

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“Yoshi kicked the bucket”

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横 飯

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横飯

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  • Small set of words with very deep meaning
  • Very efficient way of communicating
  • Difference between stranger and native user

Pattern

==

Idiom

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==

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Pattern

==

  • Idioms of C++

development

  • Language-specific
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Idiom

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Idioms in Ruby

int arr[6] = { 4, 12, 9, 13, 3, 1 }; const int size = sizeof(arr)/sizeof(arr[0]); int sum = 0; for (int i = 0; i < size; i++) { sum = sum + arr[i]; } printf("%d\n", sum);

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Idioms in Ruby

arr = [ 4, 12, 9, 13, 3, 1 ] sum = 0 for i in 0..arr.length-1 sum = sum + arr[i] end puts sum

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arr = [ 4, 12, 9, 13, 3, 1 ] sum = 0 for i in 0...arr.length sum = sum + arr[i] end puts sum

Idioms in Ruby

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Idioms in Ruby

arr = [ 4, 12, 9, 13, 3, 1 ] sum = 0 for i in 0...arr.length sum += arr[i] end puts sum

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Idioms in Ruby

sum = 0 for element in arr sum += element end puts sum

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Idioms in Ruby

sum = 0 arr.each do |element| sum += element end puts sum

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Idioms in Ruby

sum = arr.inject(0) do |total, element| total + element end puts sum

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Idioms in Ruby

sum = arr.inject do |total, element| total + element end puts sum

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Idioms in Ruby

puts arr.inject(&:+)

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Idioms in Ruby

puts %w{ Ruby World 松江市 }.inject(&:+)

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Idioms in Ruby

@value ||= calculation(data) @value || (@value = calculation(data))

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Idioms in Ruby

@cart.calculate_totals if @cart

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Idioms in Ruby

for item in items process(item) end items.each do |item| process(item) end

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Idioms

  • Concept compression
  • Learn them
  • Create your own
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Ambiguity

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  • The meaning is not 100% certain
  • Open to interpretation
  • “You get to decide”

Ambiguity

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Ambiguity

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The best poetry—the best art in any medium—is ambiguous. Ambiguity begets participation.

Daniel J. Levitin—The World in Six Songs

Ambiguity

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古池や 蛙飛こむ 水のおと

At the ancient pond the frog plunges into the sound of water —Sam Hamill 松尾芭蕉

Ambiguity

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Old pond, leap-splash – a frog. —Lucien Stryk 松尾芭蕉

Ambiguity

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古池や 蛙飛こむ 水のおと

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Breaking the silence Of an ancient pond, A frog jumped into water – A deep resonance. —Nobuyuki Yuasa 松尾芭蕉

Ambiguity

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古池や 蛙飛こむ 水のおと

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Ambiguity

At the ancient pond the frog plunges into the sound of water —Sam Hamill Old pond, leap-splash – a frog. —Lucien Stryk Breaking the silence Of an ancient pond, A frog jumped into water – A deep resonance. —Nobuyuki Yuasa

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a = 1, a = 2 p a # => [1, 2]

Ruby and Ambiguity

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p a # => 1 2

Ruby and Ambiguity

# => 2 p a = 1, a = 2

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Integer(“3”) * 2 # => 6

Ruby and Ambiguity

Integer (“3”) * 2 # => 33

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Ruby and Ambiguity

"a" "b" # => "ab" %"a" # => "a" %"b" # => "b" %"a" "b" # => "ab” %"a" %"b" # => "a"

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# => 2 2 if a = 1 && b = 2 p a, b end

Ruby and Ambiguity

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# => 2 2 if a = (1 && b = 2) p a, b end

Ruby and Ambiguity

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# WARNING! if (a = 1) && (b = 2) p a, b end

Ruby and Ambiguity

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NO!

Is this bad?

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There is no poetry Without Ambiguity

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There is no magic Without Ambiguity

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There is no fun Without Ambiguity

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And Programming Should be Fun!

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  • http://geopolicraticus.wordpress.com
  • http://www.gamefaqs.com/snes/588787-tetris-attack/images/screen-12
  • http://3dsconnect.com/2012/03/02/metal-gear-solid-snake-eater-3d-features-yoshi/
  • http://www.free-clipart-pictures.net/object_clipart.html
  • https://science.nichd.nih.gov/confluence/display/~timrozek/uploads
  • http://users.humboldt.edu/jwpowell/lwgrip.jpg
  • http://www.mypi.cn/
  • http://www.computerhistory.org/atchm/the-apl-programming-language-source-code/

Images

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