When I started programming in Haskell, where all variables are immutable, I felt like I was in a straitjacket Then, suddenly, the enlightenment
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John Carmack on mutable variables
161–170 of 663 posts
Re: John Carmack on mutable variables
#162Did you ever have one of those days when variables won't and constants aren't?
Re: John Carmack on mutable variables
#163Earlier quoted context omitted.
As a Python programmer at day job, that is Clojure-curious and sadly only gets to use it for personal projects, and is currently threatened by an obnoxious TypeScript take over, I feel this.
Removing barriers to sloppy code is a language feature. That is why vibe coding, JavaScript and Python are so attractive.
Removing barriers to civil engineering building design is a feature.
Who needs to calculate load bearing supports, walls, and floors when you can just vibe oversize it by 50%.
Re: John Carmack on mutable variables
#164After 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.
salutes from a WestLondonCoder
Re: John Carmack on mutable variables
#165How fast this got to the top, you would think John Carmack just invented nuclear fusion.
Just like AGI he was supposedly brought on board for but…..checks notes. Nothing.
Re: John Carmack on mutable variables
#166This is the mental distinction of what something represents vs what is its value. The former should never change regardless of mutability (for any sane program…), and the latter would never change for a const declaration.
The value (pun intended) of the latter is that once you’ve arrived at a concrete result, you do not have to think about it again.
You’re not defining a “variable”, you’re naming an intermediate result.
Re: John Carmack on mutable variables
#167There are languages nobody uses, and languages people complain about. Computing is about change, otherwise there is nothing to compute. The mere fact that its called a “variable” makes it obvious that its supposed to change.
Re: John Carmack on mutable variables
#168Dumb question from a primarily Python programmer who mostly writes (sometimes lengthy) scripts: if you have a function doing multiple API calls - say, to different AWS endpoints with boto3 - would you be expected to have a different variable for each response? Or do you delete the variable after it’s handled, so the next one is “new?”
Re: John Carmack on mutable variables
#169On a similar note, I’ve always liked the idea of being able to mark functions as pure (for some reasonable definition of pure). The principle of reducing state changes and side-effects feels a good one.
For what it's worth, I was experimenting with this idea for Python (in an almost completely vibe-coded fashion) here: https://github.com/jlmcgraw/pure-function-decorators
Whether it's of any actual utility is debatable
Re: John Carmack on mutable variables
#170This Carmack guy knows his stuff.