Perils of classes and pointers

When trying to understand or debug a piece of code the amount of state that one needs to keep in mind is inversely proportional with success. This leads us to an obvious advice to try to limit scope of each function to the essential components. However, there are also certain programming concepts that contribute to the amount of state one needs to track. The first one is the use of classes because class attributes are accessible in each method and may change between calls. The second one is a pointer (or reference). Pointers are problematic because, unless explicitly managed like in rust, they make it difficult to determine the owner of data at a given point of computation. This leads to uncertainty about what state a given variable may hold. Be very careful when adding classes and references to your code. Sometimes a pure function is just better.

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