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ミンコフスキ時空における物
体のフォンノイマン型計算機
上での表現について
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Just kidding
冗談です
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I want to make
SciFi come true
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● Permutation City
● Diaspora
● Matrix
● ZEGAPAIN
● etc
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OOP for Real-world
Simulation?
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“Software objects are conceptually similar
to real-world objects: they too consist of
state and related behavior”
(What is an Object — The Java Tutorials)
オブジェクトの概念は現実世界の物と似ている。それ (オブジェクト)も状態と、関連する振る舞いでできてい
る。
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“Simula is considered the first object-
oriented language. As its name implies,
Simula was designed for simulation”
(Simula — Wikipedia, Free Encyclopedia)
Simulaは世界初のオブジェクト指向言語だと考えられている。その名前の通り、 Simulaはシミュレーションの
ためにデザインされた。
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Do objects
correctly model
real-world objects?
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No!
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Things I used to point out which I do no longer
● RWOs have no knowledge about their usage
○ A book can be used to hit people
● RWOs do not respond to messages
○ Boxes do not answer when we ask them its heights
○ Instead, an external intelligence has to measure them
These mismatch become trivial if we imagine a city that
everything has a micro computer embedded into it.
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One moment please...
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What do we do?
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Functional Programming!
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History-preserving objects seem like a
natural transition from traditional objects.
● Make every instance variable immutable
● Make every method return a new object
with a reference to the current object
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A problem:
Q: Won’t this model eat up memory?
A: Not as much as you would think but Yes.
Since every object is immutable, it can be made
persistent. ∴ a new state would require a lot less space
than a full-copy. However, memory usage grows linearly
over time.
A more compact representation is needed.
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History of an object (i.e. snapshots of the past)
doesn’t have to be contained within itself
(i.e. current snapshot)
...
if we could express a 4D object directly
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Persistent Data Structures
Snapshots
Recursive Functions
Objects
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In practice, what gets folded would be a
stream of events instead of ticks of a clock.
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I call them Minkowski Objects
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● Event Stream = Blocking Queue
● Folding function writes to its neighbors’
event stream
Side-effects propagate through
various MOs’ event streams
Modifications to make MOs practical
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(fold (^ e s s’) brain [...])
(fold (^ e s s’) cup [...])
(fold (^ e s s’) mouth [...])
(fold (^ e s s’) fisher [...])
(fold (^ e s s’) stomach [...])
(fold (^ e s s’) fish [...])
(fold (^ e s s’) toilet [...])
(fold (^ e s s’) river [...])
Minkowski Object Oriented Programming
fill coffee
drink coffee
fill coffee
fill pee
add water provide oxygen
catch fish
eat fish
get smarter
get excited
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Conclusion
● Mutable objects aren’t representing anything
in real-world
破壊可能なオブジェクトは現実世界のなにも表現していない
● Functional programming can provide a more
concise analogy for real-world objects
実は関数型の方がより正確に物体を喩える事ができる
● OOP probably is too weak to make SciFi
come true
オブジェクト指向はSFを現実にするには弱すぎるのかもしれない
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