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9328 :: How to copy a random field into another of the same type at runtime?

• planetis (orginal) [2022-07-26T17:58:09+02:00] view original

  Hello!,

  I have been struggling to find a way to copy a field to another one, both chosen at runtime from a "sampler", the details of which are irrelevant, but it returns an int that corresponds to the order in which the fields are encountered. Obviously both need to be of the same type.

  So with our destination being 4, type "float" from the object Foo(a: 1, b: 2, c: new(float), d: true) that is actually .c[]. Source is 7 from Foo(a: 3, b: 4, c: nil, d: true, next: Foo(c: new(float))), that is .next.c[].

  So far I have actually implemented this with generics and recursion http://ix.io/45Jw However I feel like the solution is frankly very ugly, and could lead to stack overflows. Is there a better way to achieve this?

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• Araq (orginal) [2022-07-26T18:03:50+02:00] view original

  If you need to index into something, use an array or a seq?

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• planetis (orginal) [2022-07-26T18:19:13+02:00] view original

  I wouldn't know what you exactly mean by that, but that gave me an idea of trying to flatten all values, if that's even possible? Btw would using the RTTI module std/typeinfo an option? Is it going to be kept. Alternatively I might actually need an intermediate representation like JSON.

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• Araq (orginal) [2022-07-27T07:44:54+02:00] view original

  You can also use fields + typeof(currentField) is int. But usually it's better to change the types so that they reflect what you need to do with them. Objects don't support random access but arrays do.

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• planetis (orginal) [2022-07-27T08:53:02+02:00] view original

  Thanks for all your help Araq!

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