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Nim/changelog.md
metagn ae9287c4f3 symmetric difference operation for sets via xor (#24286) 
closes https://github.com/nim-lang/RFCs/issues/554

Adds a symmetric difference operation to the language bitset type. This
maps to a simple `xor` operation on the backend and thus is likely
faster than the current alternatives, namely `(a - b) + (b - a)` or `a +
b - a * b`. The compiler VM implementation of bitsets already
implemented this via `symdiffSets` but it was never used.

The standalone binary operation is added to `setutils`, named
`symmetricDifference` in line with [hash
sets](https://nim-lang.org/docs/sets.html#symmetricDifference%2CHashSet%5BA%5D%2CHashSet%5BA%5D).
An operator version `-+-` and an in-place version like `toggle` as
described in the RFC are also added, implemented as trivial sugar.
2024-10-19 10:07:00 +02:00

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v2.x.x - yyyy-mm-dd

Changes affecting backward compatibility

  • -d:nimPreviewFloatRoundtrip becomes the default. system.addFloat and system.$ now can produce string representations of floating point numbers that are minimal in size and possess round-trip and correct rounding guarantees (via the Dragonbox algorithm). Use -d:nimLegacySprintf to emulate old behaviors.

  • The default parameter of tables.getOrDefault has been renamed to def to avoid conflicts with system.default, so named argument usage for this parameter like getOrDefault(..., default = ...) will have to be changed.

Standard library additions and changes

  • setutils.symmetricDifference along with its operator version setutils.`-+-` and in-place version setutils.toggle have been added to more efficiently calculate the symmetric difference of bitsets.
  • std/math The ^ symbol now supports floating-point as exponent in addition to the Natural type.

Language changes

Compiler changes

Tool changes