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Dmitry Yakimenko
Dmitry Yakimenko

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Giving Go another chance: refactoring

In this session I wanted to add another command. I imagined I'd have to factor out some common code and put it elsewhere. So I started by duplicating a file and trying to build it. And then I had another Go WTF moment. Apparently I cannot have a variable or function with the same name in different files. That I didn't expect to run into. I guess it's kinda like in C, only there that would be a link error. But any intuition I had so far built up for this language just evaporated at this point.

I started googling around and found out that all the files in a package could be essentially treated as one single file. There's no such thing as a variable or a function local to a file. Can have many inits though. Anything starting with a capital letter is public and exported from the package (not file). Identifiers starting with a lowercase letter are private or hidden and are not exposed to the users of the package.

I normally refactor all the time. I move code around. I add, delete and re-add functions all the time. I rename everything constantly until I'm happy with the result. Go in general doesn't prevent this style of developing, but it makes it a bit harder by not allowing to have any unused variables or imports. The imports are easily fixed the goimports or goreturns formatting tools. The local variables have to be removed by hand. This slows down the progress for me quite a bit. I'd rather have the compiler show me a warning instead. I'd get stuff to work first and then I'd clean up the warning. Go doesn't forgive or forget.

As a result of this session I have all shared code extracted and tucked away in a separate file. I have two commands now: in and out. Things are cleaned up and are ready to be made into a great app.

Next time I start coding something more serious. Enough with the baby stuff, I'm a senior developer after all.

Google searches that went into getting this to work:

  • go private function
  • go function local to a file

Time spent: 35 minutes
Total time spent: 7:10 hours

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