Previously: https://lemmyrs.org/post/175672

I originally had sources and data of the site public, hoping they would be interesting to study, aid in bug reporting, bring contributions, and make site's algorithms transparent.

Instead, I got knee-jerk reactions about lines of code taken out of context. I got angry dogpiles from the Rust community, including rust-lang org members. I don't need to endure such mudslinging. Therefore, the sources are no longer available.

As of right now bitcoin crate is not deprecated, instead libs.rs responds with error 502.

cross-posted from: https://lemmyrs.org/post/144635

If you have a workspace with dependencies you probably noticed that sometimes cargo seemingly unnecessary recompile external dependencies as you switch between different members of your workspace.

This is caused by something called feature unification ([1]). Since features by design should be additive only cargo tries to avoid redundant work by using a superset of all required features. Problem comes when there are multiple crates in the workspace require external dependencies with different set of features. When you are working with the workspace as a whole - unified features include all the dependencies, when you target a single crate - unified features will include only features of that crate's dependencies.

What's worse - if you are using nix with crate2nix to manage dependencies - you'll get no feature unification at all and every dependency with each unique combination of features is considered a separate

If you have a workspace with dependencies you probably noticed that sometimes cargo seemingly unnecessary recompile external dependencies as you switch between different members of your workspace.

This is caused by something called feature unification ([1]). Since features by design should be additive only cargo tries to avoid redundant work by using a superset of all required features. Problem comes when there are multiple crates in the workspace require external dependencies with different set of features. When you are working with the workspace as a whole - unified features include all the dependencies, when you target a single crate - unified features will include only features of that crate's dependencies.

What's worse - if you are using nix with crate2nix to manage dependencies - you'll get no feature unification at all and every dependency with each unique combination of features is considered a separate dependency so the same crate can be compiled (and linked in) mu

What do you think about this kind of indication for conflicting or otherwise invalid arguments?

With command line arguments being 1D and line length valid up to hundreds of kilobytes only inline indication seems to work.

Would you change anything?

One of the digits of your credit card number is not like the rest of them: it's purpose is to check for value correctness, this way any website or form knows what if checksum matches - the value was typed in correctly. Or you are lucky with a typo because it's not a very good checksum - it was designed to be easy to calculate on a mechanical device and been sticking around mostly for historical reasons.

To check if a number is valid according to Luhn checksum you would go from right to left, double every second digit, add all the digits together, if result ends with 0 - checksum matches, if it ends with some other value - it does not.

For example let's check the number 1594: write down the number as a bunch of digits

 undefined

    
1 5 9 4

  

double every second digit from the right

 undefined

    
2 5 18 4

  

add all the digits

 undefined

    
2 + 5 + 1 + 8 + 4 = 20

  

ends with 0, so checksum is valid

Three key optimizations help to calculate it fast:

• You can split longer sums into short ones
• You can s