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John Carmack on mutable variables

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498 points azhenley | 2 comments | 31 Oct 25 02:34 UTC | HN request time: 0.436s | source
1. markstos ◴[31 Oct 25 20:30 UTC] No.45776373[source]▶
"State is the enemy".

Every new state is an additional condition to check. A mutated variable implies an additional state to test.

One boolean means two states to test. Four booleans that interact is 2^4 (16) states to test.

replies(1): >>45776727 #
2. baruchel ◴[31 Oct 25 21:09 UTC] No.45776727[source]▶
Which is why functional programmers believe in the separation of Church and state. https://wiki.c2.com/?SeparationOfChurchAndState