> You don't know what what_is_this is. It could be an instance variable, a method (anywhere in the inheritance tower), or an autogenerated method from method_missing. It's impossible to tell without digging through the code.
We know it's not an instance variable -- that would be @what_is_this. It would have to be a local variable, but plainly there is no such variable local to this method. So we know it's a method. Let's go hunting (we could do this vis binding.pry, or byebug, or in IRB with an instance of whatever defined some_method):
method(:what_is_this) rescue false # if false, this is coming from method_missing
method(:what_is_this).source_location # there's your definition location, if it wasn't coming from method_missing
In general I used to find debugging ruby hard, coming from a background in more static languages. Once I learned the debugging facilities it provides, finding things got a lot easier.
True. You have to learn to treat programs written in dynamic languages as living, mutable, interactive things instead of designs set in stone. However, when a simple syntax derails your reading, it is a thing of concern.
Then again, you could make similar shenanigans in Common Lisp with `symbol-macrolet', but it's obscure feature that pretty much by definition will be used only by people who know when to use it :).
> However, when a simple syntax derails your reading, it is a thing of concern.
Definitely agreed! It's rare that I've come across a set of code that is _so_ over-abstracted or dynamic that reading the code doesn't usually shed light on the issue I'm after, and usually it's a "dense" language (Scala, Lisps, etc.) that manages to achieve that.
Last time I was really, seriously confused about the code was when going through a Scala codebase written by a person deep in love with traits. My problem was less of the syntax or "denseness" and more of nonlocality - every conceptually "whole" algorithm was split into 10 or 20 files and 2 class hierarchies, each having their own hierarchy of traits.
It made some sense in the end, but it took me a lot of time to figure that one out - not because it was complicated, but didn't fit in my head. That the original author was uncooperative and didn't want to explain things too much didn't help either.
We know it's not an instance variable -- that would be @what_is_this. It would have to be a local variable, but plainly there is no such variable local to this method. So we know it's a method. Let's go hunting (we could do this vis binding.pry, or byebug, or in IRB with an instance of whatever defined some_method):
In general I used to find debugging ruby hard, coming from a background in more static languages. Once I learned the debugging facilities it provides, finding things got a lot easier.