wroc_love.rb 2016: Lessons of Liskov

Hands down the best talk of the entire weekend.

A redefinition of the Liskov Substitution Principle, giving insight to why Ruby struggles with NoMethodError on nil, why all the Rails Base classes include callbacks, and how to avoid “oh what the hell now” when you get an exception five steps from where the bug is. This talk has grown into a book: The Concise Guide to Substitutability. The video is now on YouTube.


ten minutes and already awesome @pankowecki

That was just splendid talk by @pushcx. @swistak35

10/10 talk - would listen again @michalqzajac

the talk by @pushcx on #LSP was eye-opening. thank you @siaw23

Lessons of Liskov by @pushcx was amazing - excellent content @jakubniechcial

Great talk about OOP in Ruby by @pushcx. Kill nil!@wpiekutowski

WOOOOOW, @pushcx #wrocloverb, THANK YOU! @antonpaisov

lessons on liskov by @pushcx were THE talk this year :) thanks!! @gosiaczu

best talk so far by @pushcx! 🍪clean interfaces are one of the most overlooked aspects of ruby @mrgrodo

The “Lessons of Liskov”, with no doubt, was the best talk of the conference. In four acts, Peter Bhat Harkins:

Tomek Ruskilo

Hands down the best talk of the entire weekend. Peter is an awesome speaker, he had the audience totally captivated. Plus the topic – ideas how to create easily maintainable systems through writing classes that enforce substitutability. He talked about Duck Typing and how to apply it and make it better instead of guarding for nils the entire time. Mateusz Sagan

This presentation by Peter was definitely the best during wroc_love.rb. Peter presented the liskov substitution principle and its usage in Ruby code. He talked about working with nil object, how to avoid nasty consequences that might occur regarding nils and how to make use of a NotImplementedError as a way of designing code. And of course, he elaborated superbly on Duck Typing. I strongly recommend this as a should-have-watched for every Ruby developer, no matter how experienced! Jakub Niechciał


Here's a copy of the study links from a slide near the end of the talk:

This talk has grown into a book: The Concise Guide to Substitutability.

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