Barney's Rust Playground

This project is... a playground... for Rust... for Barney. Shocking, I know.

In case it doesn't go without saying: please don't assume anything you find in here is good. Even I don't think it's good, and I wrote it to the best of my ability (at the time). There are a lot of inconsistencies, stylistic and otherwise. There's also stuff that is non-idiomatic, and even flat-out wrong. The goal is for me to play and learn, not to build a good software package.

Running

Do the rustup dance, then cargo run. You know the drill. You'll get a nice little interactive menu to run one of several utilities, all of which are of extremely little value. Except to me. For playing!

If you want to jump directly into a utility, you can supply its name on the command line:

cargo run guess

The Advent of Code Utilities

I like Advent of Code. You should give it a try if you haven't before. As well as entertaining me all December, the problems also provide nice ready-made sample apps of low - but non-trivial - complexity for playing with stuff. Like Rust!

The aoc_* utilities require an input file to read from, by default the same as the utility name with a .txt extension in the current working directory. Or they will accept a filename on the command line, after the utility name, if you don't have your input file named right. That is, these two are equivalent (but note that an input file is required either way):

cargo run aoc_2019_01
cargo run aoc_2019_01 aoc_2019_01.txt

I opted for the above naming convention as the input filenames give a good approximation to subcommand tab-completion without having to do any work. E.g. after dropping a default-named input file, enter cargo run a and hit TAB. Now you just have to delete the .txt and you're done. It gets better if you have multiple files. If you don't like my naming conventions, don't use them; the filename can be anything:

mv aoc_2019_01.txt input.txt
cargo run aoc_2019_01 input.txt

No pipes though. Sorry, man.

For Advent of Code problems that don't supply input file (e.g., 2019 day 4), copy and paste your input into a file.

Profiling

This is potentially more interesting, and potentially foolish and pointless:

cargo build
valgrind --tool=massif \
    --stacks=yes \
    --massif-out-file=massif.out \
    --detailed-freq=10000 \
    ./target/debug/rust_playground aoc_2019_03
ms_print massif.out | less

As is:

/usr/bin/time ./target/debug/rust_playground aoc_2019_03

I'm quite confident this is rather far from ideal. I'm not a systems programmer, so I'm figuring it out as I go. They did, however, help me reduce runtime of the aoc_2019_03 utility by about 20% and heap usage by about 30%.