functional programming - goto conference...protected methods: a protected method is similar to a...
TRANSCRIPT
Functional Programmingin 40 minutes
@russolsen
Functional Programmingin 40 minutes
@russolsen
Functional Programming
Functional ProgrammingClojure spin
Functional Programming40 Minutes?
What is it? What's it like? Does it work?
What is it? What's it like? Does it work?
FORGET Everything You Know About Programming
What Do You Know?
Name = ValueNames Ifs Iteration Procedures
Name = ValueNames Ifs Iteration Procedures
Strings Numerics Booleans Indentation
Name = ValueNames Ifs Iteration Procedures
Arrays HashesNamespaces
Strings Numerics Booleans Indentation
Name = ValueNames Ifs Iteration Procedures
Classes Inheritance Methods
Arrays HashesNamespaces
Strings Numerics Booleans Indentation
Name = ValueNames Ifs Iteration Procedures
Classes Inheritance Methods
Arrays HashesNamespaces
Programs
Strings Numerics Booleans Indentation
FORGET Everything You Know About ProgrammingREALLY?
Functional Programming
Everything You Know About Programming
Refactor
It Works But...
Mess
What About Programming?
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, or Object if the type parameter is unbounded.
https://docs.oracle.com/javase/tutorial/java/generics/genTypes.html
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,
or Object if the type parameter
is unbounded.
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 object that inherits from self .
https://medium.com/@tjoye20/ruby-access-control-basics-public-vs-private-vs-protected-methods-7788b26e04a7
A friend function of a class is defined outside 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
Name = ValueNames Ifs Iteration Procedures
Classes Inheritance Methods
Arrays HashesNamespaces
Programs
Strings Numerics Booleans Indentation
Messy?
Name = ValueNames Ifs Iteration
Arrays HashesNamespaces
Programs
Strings Numerics Booleans Indentation
f(x)
1
23
4
5
2
46 8
10
f(x)
1
23
4
5
2
46 8
10
Procedures
Subroutines
Functions
Methods
5 10
3 6
5 42
3 6
10 ??
5 10
36
5 10
3 6
f(x)A Thing
f(x)A Thing I Can Make
f(x)
1st Class
Look at Input
Produce Output
No Side Effects
x = ['a','b','c']
y = a(x)
x = ?
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)
Name = ValueNames Ifs Iteration
Arrays HashesNamespaces
Programs
Strings Numerics Booleans Indentation
f(x)
Problem
a b c
a b c
a Q c
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)
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)
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)
Immutable
a b c
a Q c
Problem
Copies Copies Copies
a b c d e f g h i j k l m n o p q r s t u v w x y z !
a b c d e f g h i j k l m n o p q r s t u v w x y z !
a b c d e f g h i j k l m Q o p q r s t u v w x y z !
Persistent Data Structures
a b c d e f g h i j k l m n o p q r s t u v w x y z !
a b c d e f g h i j k l m n o p q r s t u v w x y z !
m Q o
m X oQ
m X oQ
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 oQ
3
3
Name = ValueNames Ifs Iteration
Arrays* Hashes*Namespaces
Programs
Strings Numerics Booleans Indentation
f(x)
Problem
Side Effects
57Atoms
57f(x)
Atoms
58f(x)
Atoms
59f(x)
g(x)
Atoms
59f(x)
g(x)
Atoms
g(x)
some_code(queue)
Agents/Actors
f(x)
g(x)
Name = ValueNames Ifs Iteration
Arrays* Hashes*Namespaces
Programs
Strings Numerics Booleans Indentation
f(x)
What is it? What's it like? Does it work?
Magic
Magic
You still have off-by-one errors
You still have REDUNDANT code
BAD CODE
The database is STILL DOWN
Threads!
What is it? What's it like? Does it work?
pedestal.io
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 HTML pages or handle API requests.
18,706lines
28protocols
+
8bridges to the stateful world
9Record types
+
1multi method
+
944functions
f(x)
Name = ValueNames Ifs Iteration
Arrays* Hashes*Namespaces
Programs
Strings Numerics Booleans Indentation
f(x)
YES
Questions?
@russolsen
