January 2019
Intermediate to advanced
246 pages
5h 23m
English
Content preview from Programming Crystal
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Viewing the Type Hierarchy
By now, you probably suspect that there’s an entire class hierarchy at work behind every Crystal program. It can even be visualized with the crystal hierarchy tool. For example:
$ crystal tool hierarchy virtual.cr
shows all classes and structs from your program as well as the standard library. If you only want a fragment of that tree, your own classes for example, use the -e flag:
$ crystal tool hierarchy -e Document virtual.cr
This produces the following output:
Let’s make a schema for the most important types, which includes classes as well as structs (for example Int32), that can be abstract or not. Each indentation ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.