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Gentle Introduction To Funcitonal Programming - Detroit.Code

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OnorioCatenacci

This document provides an introduction to functional programming concepts. It begins by dispelling myths about FP, such as that it requires stopping OO programming or that it lacks classes. It then discusses immutability and why it is useful, defines first-class functions and how they serve like polymorphism in OO. The document also covers built-in regular expressions, and how recursion is preferred over iteration in FP due to immutable defaults. It concludes with a summary of the key topics covered.

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A Gentle Introduction To The Basics Of Functional Programming Onorio Catenacci, IT Trainer United Shore, Troy, MI
2 Agenda Dispelling Myths About FP What is Immutability and Why Should You Care? What Are First-Class Functions? Built-in Regular Expressions Recursion vs. Iteration Summary/Review
3 Myths About FP Adopting FP Ideas Means You Must Stop Writing OO Code
4 Myths About FP Adopting FP Ideas Means You Must Stop Writing OO Code Learning a New Approach Means Discarding The Old One.
5 Myths About FP Adopting FP Ideas Means You Must Stop Writing OO Code FP Doesn¡¯t Have Classes.
6 Myths About FP Adopting FP Ideas Means You Must Stop Writing OO Code You Can¡¯t Write FP in Java or C#.
7 Myths About FP FP is a New Idea
8 Myths About FP You Can Only Write FP in an FP Language
9 Myths About FP OO is More ¡°Natural¡±
10 Immutability What is Immutability and Why Should You Care i++;
11 Immutability Languages Mostly Help Or Hinder Us In Terms Of The Defaults! Developers Won¡¯t Fight Language Defaults!
12 First Class Functions What Do We Mean When We Say ¡°Function¡± In FP? let square n = n * n
13 First Class Functions What is a ¡°First Class¡± Function?
14 First Class Functions What is a ¡°First Class¡± Function? First Class Functions Serve Analogous Purpose to Polymorphism in OO.
15 First Class Functions let iseven n = n % 2 == 0 let isodd n = not iseven n let EvenIsDifferent fnForEven fnForOdd n = if iseven n then fnForEven n else fnForOdd n
16 Built-In Regular Expressions let regexDemo fn value = match (fn value) with | true -> "It's true" | false -> "Nope it's false";; regexDemo iseven 3;; // val it : string = "Nope it's false"
17 Recursion vs. Iteration By Default Values Are Immutable In FP Cannot mutate index into list for i = 0; i++; i < length(list) //Not allowed!
18 Recursion vs. Iteration Can recursively call function on list: let rec sumList lst = match lst with | [] -> 0 //Matches empty list | hd :: tl -> hd + sumList tl ;; let l = [1..100];; sumList l;; // 5050
19 Summary/Review ¡ñ FP doesn¡¯t mean ¡°Discard OO¡± ¡ñ FP has default immutability ¡ñ FP has 1st class functions ¡ñ FP emphasizes recursion over iteration.
20 Feedback Twitter: @OldDutchCap E-mail: catenacci@ieee.org Also please fill out survey: https://tinyurl.com/dcode-fp Survey is anonymous.

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Gentle Introduction To Funcitonal Programming - Detroit.Code

Editor's Notes

  1. Dispelling myths about FP What¡¯s immutability and why does it matter? What¡¯s a first class function? Built-in regular expressions Recursion vs. iteration Summary/review
  2. Someone seems to have gotten the mistaken notion that adopting FP means dropping OO; nothing could be further from the truth. Let¡¯s look at a few of the assumptions underlying that: 1.) Learning a new approach means abandoning an old approach. 2.) FP doesn¡¯t have classes
  3. Someone seems to have gotten the mistaken notion that adopting FP means dropping OO; nothing could be further from the truth. Let¡¯s look at a few of the assumptions underlying that: 1.) Learning a new approach means abandoning an old approach. 2.) FP doesn¡¯t have classes
  4. Someone seems to have gotten the mistaken notion that adopting FP means dropping OO; nothing could be further from the truth. Let¡¯s look at a few of the assumptions underlying that: 1.) Learning a new approach means abandoning an old approach. 2.) FP doesn¡¯t have classes
  5. Someone seems to have gotten the mistaken notion that adopting FP means dropping OO; nothing could be further from the truth. Let¡¯s look at a few of the assumptions underlying that: 1.) Learning a new approach means abandoning an old approach. 2.) FP doesn¡¯t have classes