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John Carmack on mutable variables

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498 points azhenley | 1 comments | 31 Oct 25 02:34 UTC | HN request time: 0.223s | source
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EastLondonCoder ◴[31 Oct 25 09:30 UTC] No.45770007[source]▶
After a 2 year Clojure stint I find it very hard to explain the clarity that comes with immutability for programmers used to trigger effects with a mutation.

I think it may be one of those things you have to see in order to understand.

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1. bjoli ◴[01 Nov 25 12:39 UTC] No.45781186[source]▶
I spent some time discussing in another thread discussing why the foreach loop is so bad in many languages. Most of the bugs I write come from me managing state, yet if I want to do much more than going start to end of a collection I have to either use methods that are slower than a proper loop or I have to manage all the state myself.

In common lisp you have the loop macro (or better: iterate), in racket you have the for loops. I wrote a thing for guile scheme [0]. Other than that I dont know if many nice looping facilities. In many languages you can achieve all that with conbinatoes and what not, but always at the cost of performance.

I think this is an opportunity for languages to become safer and easier to use without changing performance.

0:https://rikspucko.koketteriet.se/bjoli/goof-loop