testing map key existence

[Dan Kortschak]

There is has(e.f) when statically testing object e for existence of the
field f, but I cannot see an obvious way to do the equivalent when we
have a map, m and a key, k. How can I express what would be has(m[k]),
but isn't? At the moment I'm using our is_error (consumes a ref.Val
which may be an error and returns a boolean if it is) extension as
!is_error(m[k]).

Dan

[Tristan Swadell]

Hi Dan,

The best way to test for map key presence would be to use `in`: e.g. `k in m`. Also consider using OptionalTypes to improve ease of use.

Hope that helps,

-Tristan

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[Dan Kortschak]

On Thu, 2023-07-13 at 12:34 -0700, 'Tristan Swadell' via CEL Go

Discussion Forum wrote:
> The best way to test for map key presence would be to use `in`: e.g.
> `k in m`. Also consider using OptionalTypes to improve ease of use.
>
> Hope that helps,

Thanks, Tristan. This is perfect.

Dan

[Dan Kortschak]

On Thu, 2023-07-13 at 12:34 -0700, 'Tristan Swadell' via CEL Go

Discussion Forum wrote:
> Also consider using OptionalTypes to improve ease of use.

Just following this up. From the docs, adding OptionalTypes into an env
looks like it is backwards compatible, but I'd just like to check that
that is the case.

thanks
Dan

[Tristan Swadell]

Hi Dan,

Optional types are backwards compatible.

Cheers,

-Tristan

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