# Unsure about properties

**URL:** <https://discourse.julialang.org/t/unsure-about-properties/110756>\
**Category:** General Usage\
**Tags:** properties\
**Created:** [February 26, 2024, 4:10am UTC](https://discourse.julialang.org/t/unsure-about-properties/110756 "2024-02-26T04:10:46Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![GunnarFarneback](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/gunnarfarneback/32/1827_2.png) [@GunnarFarneback](https://discourse.julialang.org/u/GunnarFarneback)\
**Post date:** [February 26, 2024, 9:06am UTC](https://discourse.julialang.org/t/unsure-about-properties/110756/3 "2024-02-26T09:06:43Z")

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  1. Sure, you can use `_` as a field name so I don’t see why you couldn’t use it as a property name. Either case is kind of user unfriendly though, since property destructuring, `(; _) = S()`, puts your field into a write-only variable.

- 2-4. Don’t mess with properties of types you don’t own. (`S` is yours, but not `typeof(S)`).
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  1. The most obvious consequence is that you can’t tab-complete your properties in the REPL.

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  1. You need to be very careful with only using `getfield` to access your real fields inside your `getproperty` and `setproperty!` implementations, to avoid performance traps.

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