To me, parametric polymorphism is much nicer for reasoning about a program locally / modularly. It's kind of like reasoning about a function with linear control

To me, parametric polymorphism is much nicer for reasoning about a program locally / modularly. It's kind of like reasoning about a function with linear control flow vs reasoning about a function with lots of nested if/elses. You can do the reasoning once and be done with it. I tried to make a general point along those lines in this blog post, thought I think it deserves more extensive examples. http://storm-country.com/blog/abstract-is-simple http://storm-country.com/blog/abstract-is-simple