rust_cmd_lib VS too-many-lists

With rust_cmd_lib, you can write below code without launching shell:

zsh is also doing the variable substitution better than bash. FYI, I just released rust_cmd_lib 1.0 recently, which can do variable substitution without any quotes: https://github.com/rust-shell-script/rust_cmd_lib

With cmd_lib and rayon, it could be done in below one line code:

#!/usr/bin/env ngs # In response to https://github.com/rust-shell-script/rust_cmd_lib/blob/1f2fc2303db3f467c42589bd944b31834c8a0bca/examples/dd_test.rs # $ ./dd_test.ngs --file /dev/nvme0n1 --block_size 4096 --threads_count 4 # [LOG 2021-03-20 10:57:14 IST] Dropping caches at first # [LOG 2021-03-20 10:57:14 IST] Running command: sudo bash -c echo\ 3\ \>\ /proc/sys/vm/drop_caches # [LOG 2021-03-20 10:57:15 IST] Running with threads: 4, block size: 4096 # [LOG 2021-03-20 10:57:15 IST] Running command: sudo bash -c dd\ if=/dev/nvme0n1\ of=/dev/null\ bs=4096\ skip=1310720\ count=655360\ 2\>\&1 # [LOG 2021-03-20 10:57:15 IST] Running command: sudo bash -c dd\ if=/dev/nvme0n1\ of=/dev/null\ bs=4096\ skip=655360\ count=655360\ 2\>\&1 # [LOG 2021-03-20 10:57:15 IST] Running command: sudo bash -c dd\ if=/dev/nvme0n1\ of=/dev/null\ bs=4096\ skip=1966080\ count=655360\ 2\>\&1 # [LOG 2021-03-20 10:57:15 IST] Running command: sudo bash -c dd\ if=/dev/nvme0n1\ of=/dev/null\ bs=4096\ skip=0\ count=655360\ 2\>\&1 # [LOG 2021-03-20 10:57:22 IST] thread 0 bandwidth: 450 MB/s # [LOG 2021-03-20 10:57:22 IST] thread 1 bandwidth: 451 MB/s # [LOG 2021-03-20 10:57:22 IST] thread 2 bandwidth: 453 MB/s # [LOG 2021-03-20 10:57:22 IST] thread 3 bandwidth: 451 MB/s # [LOG 2021-03-20 10:57:22 IST] Total bandwidth: 1805 MB/s # Command line arguments automatically fed into main() # Default data size - 10G F main(file:Str, block_size:Int=4096, threads_count:Int=1, data_size:Int=10 * 1024 * 1024 * 1024) { log("Dropping caches at first") $(log: sudo bash -c "echo 3 > /proc/sys/vm/drop_caches") log("Running with threads: ${threads_count}, block size: ${block_size}") # Parallel map: each callback runs in it's own thread cnt = data_size / threads_count / block_size results = threads_count.pmap(F(i) { off = cnt * i `log: sudo bash -c "dd if=$file of=/dev/null bs=$block_size skip=$off count=$cnt 2>&1"` }) total_bandwidth = 0 results.each_idx_val(F(i, output) { # "line:" makes the first line of output as the result of `...` bandwidth = `echo $output | line: awk '/MB/ {print $10}'`.Int() log("thread ${i} bandwidth: ${bandwidth} MB/s") total_bandwidth += bandwidth }) log("Total bandwidth: $total_bandwidth MB/s") } # When running without arguments F main() { # exit() - exit code is 1 unless otherwise specified exit("Usage: ${ARGV0} --file FILE [--block_size BLOCK_SIZE] [--threads_count THREADS_COUNT] [--data_size DATA_SIZE]") }

Thanks for the inspiration from previous posts, and I tried to convert pipes.sh to rust code today. It turned out to be very straightforward with the help of rust_cmd_lib, and your can check both language versions in the project examples directory.

Yes, your concern is correct and that's why I encourage people to use macros by default: https://github.com/rust-shell-script/rust_cmd_lib#security-notes

You seem to have a preset opinion, and I'm not sure you are interested in re-evaluating it. So this is not written to change your mind.

I've developed production code in C, C++, Rust, and several other languages. And while like pretty much everything, there are situations where it's not a good fit, I find that the solutions tend to be the most robust and require the least post release debugging in Rust. That's my personal experience. It's not hard data. And yes occasionally it's annoying to please the compiler, and if there were no trait constraints or borrow rules, those instances would be easier. But way more often in my experience the compiler complained because my initial solution had problems I didn't realize before. So for me, these situations have been about going from building it the way I wanted to -> compiler tells me I didn't consider an edge case -> changing the implementation and or design to account for that edge case. Also using one example, where is Rust is notoriously hard and or un-ergonomic to use, and dismissing the entire language seems premature to me. For those that insist on learning Rust by implementing a linked list there is https://rust-unofficial.github.io/too-many-lists/.

Advent of Code was okay until I encounterd a problem that required a graph, tree or linked list to solve, where I hit a wall. Most coding exercises are similar--those requiring arrays and hashmaps and sets are okay, but complex data structures are a PITA. (There is an online course dedicated to linked lists in Rust but I couldn't grok it either). IMO you should simply skip problems that you can't solve with your current knowledge level and move on.

I feel obligated to point to the original cannon literature: https://rust-unofficial.github.io/too-many-lists/

I started learning Rust and like how the compiler is fussy about things. My plan was to implement the data structures I knew, but I got stuck at the singly linked list's remove() method. I've read the book as well, but I have no clue how to simplify this further:

My impression from the article is that Zig provides several different hashtables and not all of them are broken in this way.

This reminds me of Aria's comment in her Rust tutorial https://rust-unofficial.github.io/too-many-lists/ about failing to kill LinkedList. One philosophy (and the one Rust chose) for a stdlib is that this is only where things should live when they're so commonly needed that essentially everybody needs them either directly or to talk about. So, HashTable is needed by so much otherwise unrelated software that qualifies, BloomFilter, while it's real useful for some people, not so much. Aria cleaned out Rust's set of standard library containers before Rust 1.0, trying to keep only those most people would need. LinkedList isn't a good general purpose data structure, but, it was too popular and Aria was not able to remove it.

Having multiple hash tables feels like a win (they're optimized for different purposes) but may cost too much in terms of the necessary testing to ensure they all hit the quality you want.

> Cyclic references can be dealt with runtime safety checks too - like Rc and Weak.

Indeed. Starting out with code sprinkled with Rc, Weak, RefCell, etc is perfectly fine and performance will probably not be worse than in any other safe languages. And if you do this, Rust is pretty close to those languages in ease of use for what are otherwise complex topics in Rust.

A good reference for different approaches is Learn Rust With Entirely Too Many Linked Lists https://rust-unofficial.github.io/too-many-lists/

Second, once you've finished something introductory like The Book, read Learning Rust With Entirely Too Many Linked Lists. It really helped me to understand what ownership and borrowing actually mean in practical terms. If you don't mind paying for learning materials, a lot of people recommend Programming Rust, Second Edition by Blandy, Orendorff, and Tindall as either a complement, follow-up, or alternative to The Book.

Learning Rust With Entirely Too Many Linked Lists which highlights a lot of the differences with how you need to structure your code in Rust compared to other languages.