Comment on The temptation is always there

SquishyPandaDev@yiffit.net ⁨11⁩ ⁨months⁩ ago

• magic_lobster_party@kbin.social ⁨11⁩ ⁨months⁩ ago

  The definition of a variable is that it’s mutable. If it’s immutable it’s constant.

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  • marcos@lemmy.world ⁨11⁩ ⁨months⁩ ago

    There’s no ISO standardized definition for variable. People use that word with all kinds of meaning.

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    • drcouzelis@lemmy.zip ⁨11⁩ ⁨months⁩ ago

      Waaaait a minute… isn’t it called a variable because the contents are, you know, variable?

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      • BassTurd@lemmy.world ⁨11⁩ ⁨months⁩ ago

        It started as a variable, then ended as a constant.

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    • Yen@feddit.uk ⁨11⁩ ⁨months⁩ ago

      This is needlessly obtuse. The definition of the word is that it’s non-constant. There isn’t an ISO definition of the word no, but there are many reputable dictionaries out there that will serve as an alternative.

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      • marcos@lemmy.world ⁨11⁩ ⁨months⁩ ago

        Well, starting with the definition from algebra, where it’s not something allowed to vary…

        I guess more people know about math than use imperative programing languages.

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  • Walnut356@programming.dev ⁨11⁩ ⁨months⁩ ago

    I feel like it’s like pointers.

    “Variable” refers to the label, i.e. a box that can contain anything (like *ptr is a pointer to [something we dont know anything about])

    Immutable describes the contents, i.e. the stuff in the box cant change. (like int* ptr is a pointer to an int)

    Rust makes it very obvious that there’s a difference between constants and immutable variables, mainly because constants must be compile time constants.

    What do you call it when a variable cant change after its definition, but isnt guaranteed to be the same on each function call? It’s not a constant, the contents of that label are “changing”, but the label’s contents cant be modified inside the scope of that function. So it’s a variable, but immutable.

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• QuazarOmega@lemy.lol ⁨11⁩ ⁨months⁩ ago

  As opposed to immutable variables

  *confused screaming*

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  • yiliu@informis.land ⁨11⁩ ⁨months⁩ ago

    Or mutable constants…

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    • Eufalconimorph@discuss.tchncs.de ⁨11⁩ ⁨months⁩ ago

      int const golden = 1.618;
      int* non_constant = (int*)&golden;
      golden = 1.61803399;
      

      Casts are totally not a danger that should require a comment explaining safety…

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• Eufalconimorph@discuss.tchncs.de ⁨11⁩ ⁨months⁩ ago

  And more generally mutable aliasing references of any sort are evil. Doesn’t mean they’re not useful, just that you need magic protection spells (mutexes, semaphores, fancy lock-free algorithms, atomics, etc) to use them safely. Skip the spell or use she wrong one, and the demon escapes and destroys all you hold dear.

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