Rust's Block Pattern
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Rust's Block Pattern
1–10 of 121 posts
Re: Rust's Block Pattern
#2I love that this is part of the syntax.
I typically use closures to do this in other languages, but the syntax is always so cumbersome. You get the "dog balls" that Douglas Crockford always called them:
``` const config = (() => { const raw_data = ...
...
return compiled;const result = config.whatever;
// carry on
return result; ```
Really wish block were expressions in more languages.
Re: Rust's Block Pattern
#3It's idiomatic in Kotlin as well!
Re: Rust's Block Pattern
#4It's idiomatic in Kotlin as well! https://kotlinlang.org/docs/scope-functions.html
I agree, i started with (scope) blocks in Rust, but keep the habit in Kotlin win the run - scope-function. Since run takes no arguments, it feels like the closest equivalent to Rust scopes (compared to other Korlin scope functions, which also keep their local variables from polluting the rest of the function body).
Re: Rust's Block Pattern
#5The first example given is not at all convincing. Its is clear as the sky that loading the config file should be be a separate function of its own. Coupling sending HTTP requests with it makes no sense.
The second example "erasure of mutability" makes more sense. But this effectively makes it a Rust-specific pattern.
Re: Rust's Block Pattern
#6I have one better: the try block pattern.
https://doc.rust-lang.org/beta/unstable-book/language-featur...
Re: Rust's Block Pattern
#7It's idiomatic in Kotlin as well! https://kotlinlang.org/docs/scope-functions.html
So many options why oh why. let run with also apply
Re: Rust's Block Pattern
#8You can also de-mut-ify a variable by simply shadowing it with an immutable version of itself:
let mut data = foo(); data.mutate(); let data = data;
May be preferable for short snippets where adding braces, the yielded expression, and indentation is more noise than it's worth.
Re: Rust's Block Pattern
#9GCC adds similar syntax as an extension to C: https://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html
It's used all throughout the Linux kernel and useful for macros.
Re: Rust's Block Pattern
#10This seems like a great way to group semantically-related statements, reduce variable leakage, and reduce the potential to silently introduce additional dependencies on variables. Seems lighter weight (especially from a cognitive load perspective) than lambdas. Appropriate for when there is a single user of the block -- avoids polluting the namespace with additional functions. Can be easily turned into a separate function once there are multiple users.