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Functional Programming
in 40 minutes @russolsen
Functional Programming in 40 minutes @russolsen Functional - - PowerPoint PPT Presentation
Functional Programming in 40 minutes @russolsen Functional - - PowerPoint PPT Presentation
Functional Programming in 40 minutes @russolsen Functional Programming in 40 minutes @russolsen Functional Programming Functional Programming Clojure spin Functional Programming 40 Minutes? What is it? What's it like? Does it work?
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Functional Programming
in 40 minutes @russolsen
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Functional Programming
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Functional Programming
Clojure spin
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Functional Programming
40 Minutes?
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What is it? What's it like? Does it work?
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What is it? What's it like? Does it work?
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FORGET
Everything You Know About Programming
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What Do You Know?
SLIDE 13 Name = Value Names Ifs Iteration Procedures
SLIDE 14 Name = Value Names Ifs Iteration Procedures Strings Numerics Booleans Indentation
SLIDE 15 Name = Value Names Ifs Iteration Procedures Arrays Hashes Namespaces Strings Numerics Booleans Indentation
SLIDE 16 Name = Value Names Ifs Iteration Procedures Classes Inheritance Methods Arrays Hashes Namespaces Strings Numerics Booleans Indentation
SLIDE 17 Name = Value Names Ifs Iteration Procedures Classes Inheritance Methods Arrays Hashes Namespaces Programs Strings Numerics Booleans Indentation
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FORGET
Everything You Know About Programming
REALLY?
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Functional Programming
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Everything You Know About Programming
Refactor
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It Works But...
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Mess
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What About Programming?
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During the type erasure process, the Java compiler erases all type parameters and replaces each with its first bound if the type parameter is bounded,
- r Object if the type parameter
is unbounded.
https://docs.oracle.com/javase/tutorial/java/generics/genTypes.html SLIDE 36
During the type erasure process, the Java compiler erases all type parameters and replaces each with its first bound if the type parameter is bounded,
- r Object if the type
parameter is unbounded.
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Protected methods: a protected method is similar to a private method, with the addition that it can be called with, or without, an explicit receiver, but that receiver is always self (it’s defining class) or an
- bject that inherits from self .
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A friend function of a class is defined
- utside that class' scope but it has the
right to access all private and protected members of the class. Even though the prototypes for friend functions appear in the class definition, friends are not member functions.
https://www.tutorialspoint.com/cplusplus/cpp_friend_functions.htm SLIDE 39 Name = Value Names Ifs Iteration Procedures Classes Inheritance Methods Arrays Hashes Namespaces Programs Strings Numerics Booleans Indentation
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Messy?
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SLIDE 42 Name = Value Names Ifs Iteration Arrays Hashes Namespaces Programs Strings Numerics Booleans Indentation
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f(x)
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1 2 3 4 5 2 4 6 8 10
f(x)
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1 2 3 4 5 2 4 6 8 10
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Procedures Subroutines Functions Methods
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5 10 3 6
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5 42 3 6 10 ??
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5 10 3 6
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5 10 3 6
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f(x)
A Thing
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f(x)
A Thing I Can Make
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f(x)
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1st Class
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Look at Input Produce Output
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No Side Effects
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x = ['a','b','c'] y = a(x) x = ?
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x = ['a','b','c'] y = x = ?
c(a(x) + b(x)) + d(x) * e(x) - 4 * (q(x) - f(x)) + d(x) * e(x) - 4 * (q(x) - f(x)) + b(x)) + d(x) / c(a(x) + b(x)) + d(x) * e(x) + g(x) + h(x) * floor(b(x)) + 16 * a(x) - ceil(g(x) - c(a(x) + b(x)) + d(x) * e(x) - 4 * (q(x) - f(x)) + d(x) * e(x) - 4 * (q(x) - f(x)) + b(x)) + d(x) / c(a(x) + b(x)) + d(x) * e(x) + g(x) + h(x) * floor(b(x)) + 16 * a(x) SLIDE 66 Name = Value Names Ifs Iteration Arrays Hashes Namespaces Programs Strings Numerics Booleans Indentation
f(x)
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Problem
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a b c
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a b c
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a Q c
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x = ['a','b','c'] y = x = ?
c(a(x) + b(x)) + d(x) * e(x) - 4 * (q(x) - f(x)) + d(x) * e(x) - 4 * (q(x) - f(x)) + b(x)) + d(x) / c(a(x) + b(x)) + d(x) * e(x) + g(x) + h(x) * floor(b(x)) + 16 * a(x) - ceil(g(x) - c(a(x) + b(x)) + d(x) * e(x) - 4 * (q(x) - f(x)) + d(x) * e(x) - 4 * (q(x) - f(x)) + b(x)) + d(x) / c(a(x) + b(x)) + d(x) * e(x) + g(x) + h(x) * floor(b(x)) + 16 * a(x) SLIDE 72 t = c(a(x) + b(x)) + d(x) * e(x) - 4 * (q(x) - f(x)) + d(x) * e(x) - 4 * (q(x) - f(x)) + b(x)) + d(x) / c(a(x) + b(x)) + d(x) * e(x) + g(x) + h(x) * floor(b(x)) + 16 * a(x) - ceil(g(x) x[2] = 'Q' y = t + c(a(x) + b(x)) + d(x) * e(x) - 4 * (q(x) - f(x)) + d(x) * e(x) - 4 * (q(x) - f(x)) + b(x)) + d(x) / c(a(x) + b(x)) + d(x) * e(x) + g(x) + h(x) * floor(b(x)) + 16 * a(x)
SLIDE 73 t = c(a(x) + b(x)) + d(x) * e(x) - 4 * (q(x) - f(x)) + d(x) * e(x) - 4 * (q(x) - f(x)) + b(x)) + d(x) / c(a(x) + b(x)) + d(x) * e(x) + g(x) + h(x) * floor(b(x)) + 16 * a(x) - ceil(g(x)
x[2] = 'Q'
y = t + c(a(x) + b(x)) + d(x) * e(x) - 4 * (q(x) - f(x)) + d(x) * e(x) - 4 * (q(x) - f(x)) + b(x)) + d(x) / c(a(x) + b(x)) + d(x) * e(x) + g(x) + h(x) * floor(b(x)) + 16 * a(x) SLIDE 74
Immutable
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a b c a Q c
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Problem
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Copies Copies Copies
SLIDE 78 a b c d e f g h i j k l m n
- p
SLIDE 79 a b c d e f g h i j k l m n
- p
- p
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Persistent Data Structures
SLIDE 81 a b c d e f g h i j k l m n
- p
SLIDE 82 a b c d e f g h i j k l m n
- p
SLIDE 83 m Q o
SLIDE 84 m X
- Q
SLIDE 85 m X
- Q
SLIDE 86 a b c d e f g h i j k l p q r s t u v w x y z ! m X
- Q
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3
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3
SLIDE 89 Name = Value Names Ifs Iteration Arrays* Hashes* Namespaces Programs Strings Numerics Booleans Indentation
f(x)
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Problem
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Side Effects
SLIDE 92 Russ Olsen russ@russolsen.com
SIDE EFFECTS
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EFFECTS
Russ Olsen russ@russolsen.com SLIDE 94
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Atoms
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57
f(x)
Atoms
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f(x)
Atoms
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f(x) g(x)
Atoms
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f(x) g(x)
Atoms
g(x)
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some_code(queue)
Agents/Actors
f(x) g(x)
SLIDE 101 Name = Value Names Ifs Iteration Arrays* Hashes* Namespaces Programs Strings Numerics Booleans Indentation
f(x)
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What is it? What's it like? Does it work?
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Magic
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Magic
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You still have
- ff-by-one
errors
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You still have REDUNDANT code
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BAD CODE
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The database is
STILL DOWN
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Threads!
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What is it? What's it like? Does it work?
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pedestal.io
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What is Pedestal?
Pedestal is a set of libraries that we use to build services and- applications. It runs in the back end and can serve up whole
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18,706
lines
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28
protocols
+
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8
bridges to the stateful world
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9
Record types
+
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1
multi method
+
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944
functions
f(x)
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SLIDE 123 Name = Value Names Ifs Iteration Arrays* Hashes* Namespaces Programs Strings Numerics Booleans Indentation
f(x)
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YES
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Questions?
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@russolsen
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