Understanding Objective-C square brackets

Mark Dalrymple:

What is something that we use every day as a Mac or iOS programmer? Objective-C. What do we use every day in Objective-C? Those square brackets. How many times a day do you type something like this?

[someObject doSome:stuff for:reasons];

Ever wondered what’s really happening inside those square brackets?

Mark delivers an impressive dive well beyond the brackets of Objective-C.