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Merge pull request #14552 from hsjobeki/docs-sort

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docs: add explanation to sort primop
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Sergei Zimmerman 2025-12-16 20:31:12 +00:00 • committed by GitHub
commit e0830681e2
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1 changed files with 18 additions and 2 deletions
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18
src/libexpr/primops.cc
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@ -4061,6 +4061,8 @@ static RegisterPrimOp primop_sort({
1. Transitivity
If a is less than b and b is less than c, then it follows that a is less than c.
```nix
comparator a b && comparator b c -> comparator a c
```
@ -4073,8 +4075,22 @@ static RegisterPrimOp primop_sort({
1. Transitivity of equivalence
First, two values a and b are considered equivalent with respect to the comparator if:
```
!comparator a b && !comparator b a
```
In other words, neither is considered "less than" the other.
Transitivity of equivalence means:
If a is equivalent to b, and b is equivalent to c, then a must also be equivalent to c.
```nix
let equiv = a: b: (!comparator a b && !comparator b a); in
let
equiv = x: y: (!comparator x y && !comparator y x);
in
equiv a b && equiv b c -> equiv a c
```