Function for building and running a rust script using local build directory

rustr.fish

function rustr
    if test (count $argv) -ne 1
        echo "Usage: rustr <filename>"
        return 1
    end

    set filename $argv[1]
    set output_file (string replace -r '\.rs$' '' $filename)

    # Create the build directory if it doesn't exist
    mkdir -p ./build

    # Compile the file
    rustc $filename -o ./build/$output_file
    and ./build/$output_file
end