[swift-users] What are .swift.gyb files?

Brent Royal-Gordon brent at architechies.com
Tue Dec 8 08:38:14 CST 2015

> I'm reading the stdlib source code and I see .gyb files. What are those files for? 

gyb stands for Generate Your Boilerplate. It’s a preprocessor the Swift team wrote so that when they needed to build, say, ten nearly-identical variants of Int, they wouldn’t have to literally copy and paste the same code ten times. If you open one of those files, you’ll see that they’re mainly Swift code, but with some lines of code intermixed that are written in Python. The actual preprocessor itself is in the Swift source repository at utils/gyb, though most of the code is in utils/gyb.py.

Brent Royal-Gordon

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