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0 pointsfastest9633y ago0 comments

This is why all the examples call Store immediately with a zero value of the type.

0 comments

Interfaces don't have a zero type, which means that we can't have an atomic.Value which stores Shape. Atomic Value would be much easier to reason about if it had store semantics similar to a regular `var foo Shape = ...`. One of the other comment threads talked about generics helping this, so maybe there is hope.

yencabulator3y ago

Parent means

    var bestShape atomic.Value
    bestShape.Store((*Circle)(nil))

morelisp3y ago

Which will store it as a *Circle, and only allow more *Circles, not Shapes. That part of GP’s claim is correct.

It just had nothing to do with atomicity; it means something specific, not just “I like the failure mode.”

yencabulator3y ago

That's pretty easy to workaround:

    type shapeContainer struct { Shape }

The usual way to use atomic.Value is by writing strongly-typed wrappers anyway, so that doesn't affect your codebase beyond about 3 lines.

j / k navigate · click thread line to collapse

0 comments

bumper_crop3y ago

https://go.dev/play/p/xolc9oPwA0C

yencabulator3y ago

Parent means

    var bestShape atomic.Value
    bestShape.Store((*Circle)(nil))

morelisp3y ago

Which will store it as a *Circle, and only allow more *Circles, not Shapes. That part of GP’s claim is correct.

It just had nothing to do with atomicity; it means something specific, not just “I like the failure mode.”

yencabulator3y ago

That's pretty easy to workaround:

    type shapeContainer struct { Shape }

The usual way to use atomic.Value is by writing strongly-typed wrappers anyway, so that doesn't affect your codebase beyond about 3 lines.

j / k navigate · click thread line to collapse