doc: add some array usage examples

[tshepang]

No description provided.

[rust-highfive]

r? @pcwalton

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[bluss]

Looks good. Isn't this a nice place to explain how certain traits are implemented just for array sizes 0-32? Maybe mention information that's not visible in the API documentation:

• [T; N] is an array type for any compile time constant N (>= 0).
• Array creation [x; N] and [x, y, z].
• Array is Copy as long as the element type is Copy.
• Arrays always derefence to slices, so they have slice methods too.

[tshepang]

@bluss I don't mind if you add that extra info to either this PR or a follow-up... I don't have the knowledge of those things you mention.

[bluss]

Sounds like they need to be documented then!

[bluss]

@bors: r+ rollup

thanks! This is the starting point

[bors]

📌 Commit c4c5c2d has been approved by bluss

[bors]

⌛ Testing commit c4c5c2d with merge 92a95fe...

[tshepang]

Take the following @bluss:

Array creation [x; N] and [x, y, z].

Did you mean that I should mention that one doesn't need to explicitly mention the type (i.e. [i32; 3])?

[bluss]

No but that (the expression) [x; N] creates a fixed size array (if the type of x is Copy) where every element has value x.

[bors]

☀️ Test successful - auto-linux-32-nopt-t, auto-linux-32-opt, auto-linux-64-nopt-t, auto-linux-64-opt, auto-linux-64-x-android-t, auto-mac-32-opt, auto-mac-64-nopt-t, auto-mac-64-opt, auto-win-gnu-32-nopt-t, auto-win-gnu-32-opt, auto-win-gnu-64-nopt-t, auto-win-gnu-64-opt

[bluss]

#26923 is the follow-up