Rust Ruby Exercise 1

#Simple Rust lib consumed by Ruby via FFI

This test is intended as a simple exercise. The intentions:

• to make Rust consume a text file and parse through it, line by line
• to not load the entire file in memory before parsing (I/O streaming, line by line)
• to test the currently available Regex support
• to test how to expose such a function for FFI comsumption
• to benchmark a similar Ruby solution

So far, be careful:

• the Regex library seems to be slow so far
• it's so slow that the Rust solution is actually a bit slower than the Ruby one (!!)
• I might be making basic mistakes in the Rust code (still just 5 days into studying)

Running Rust 1.0 and Ruby 2.2.2, this is the benchmark with a 1_000_000 slice from the actors.list file:

RUST: 7.270000   0.070000   7.340000 (  7.363527)
RUBY: 6.020000   0.030000   6.050000 (  6.082596)

I believe that the regex lib is the culprit at this point, but not sure how to profile.

If I'm making obvious mistakes, a pull request will be really appreciated.

To run the test:

cargo build --release
cargo run --release

Or to run via Ruby+FFI:

RUST=1 ruby actors.rb