Intro to
Functional Programming
By - Prakash Balodi
I Am
Software Engineer @ Quintype Inc.
Prakash Balodi
Agenda
- What is Functional programming
- Pure functions & Immutability
- State, Identity and Value
- Higher Order functions
State of the Art!
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Complex software systems
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Huge Codebases
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Distributed systems (Architecture & Infrastructure)
What is FP ?
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Programming mostly with pure functions
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Functions take data and return data
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Higher order functions
Pure Functions
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Functions that are without side effects
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Only return values, do not affect world
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in any other way
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For same input, output is also same (Referential Transparency)
int x= 10;
Math.sqrt(10); //Pure
new Random.nextInt() //Impure
Advantages of Pure Functions
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Code is easier to debug,
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Code can be lazy (or executed multiple times)
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Function Calls can be Memoized.
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Context for a function is small => easier to test
Person p = new Person(name: "Prakash", age:27);
println p.name // Prakash
foo(p);
bar(p);
println p.name // maybe Prakash?
Immutability
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Basically means that value of a variable cant be changed.
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Enforces Functions to be simple (and testable)
State, Identity and Value
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Value signifies the meaning or worth of something.
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Traditional programming assumes little difference between value and identity.
int x = 50;
// 50 is the value
//x is the identity.Values don't have time associated with them, Identities do
int x = 50; //Value of x at time t1
x = x*2; //Value of x at time t2
x = 80; //Value of x at time t3
Thanks!
- Simplicity Matters - https://www.youtube.com/watch?v=rI8tNMsozo0
- FP and Battle for survival - https://www.youtube.com/watch?v=_6cDgwIHtQw
- Clojure for Java programmers - https://www.youtube.com/watch?v=P76Vbsk_3J0
Why Clojure?
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REPL is awesome!
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Java Ecosystem (libs and Interop)
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Beautiful Sequence API