jank

The “Jankiest” way of writing Ruby gems

Recently I wrote about a Jank, the programming language that is able to bring Cojure to the native world using LLVM. I also mentioned that Jank is not yet ready for production usage – and that is just true; it still have many bugs that prevent us to use it for more complex problems, and maybe even some simple ones.

That doesn’t mean we can’t try it, and see how bright the future might be.

At my last post I ended up showing in an example of a Ruby code. Later, after many problems trying to make something more complex, I finally was able to hack up some solution that bypasses some of the bugs that Jank still have.

And let me tell you, even in the pre-alpha stage that the language is, I can already see some very interesting things – the most important one being the “interactive development” of the native extension – or if you want to use the Ruby terms, monkey patching native methods.
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By Maurício Szabo, ago

Calling Jank from C

For those that don’t know, Jank is a Clojure implementation but instead of targeting Java, it targets LLVM (Low-Level Virtual Machine). That means, Jank compiles to native code, and interops directly with C++.

Jank already have ways to call C++, but I wanted to do the opposite – to call Jank’s code from C. The reason might not be obvious, so here is an why: writing libraries.

Not all things need to be “stand-alone executables”. One example is libraries for Node, for Ruby, or Python. These languages are amazing on the levels of abstraction they support, and it’s easy to interact directly with code and their runtime (in Node, using Devtools, in Ruby, using something like pry or Lazuli, my own plug-in). They are also quite slow, and in some cases, we might need to call some native API that these languages don’t support. So what now? The canonical way is to write some extension in C or C++; now we have to manually manipulate memory and deal with safety issues (and before people say something about it “not being that hard”, it is. Most of CVEs happen because of manual memory manipulation in C – every cast, every printf, every strcpy can cause ACE and/or privilege escalation issues). They are also not interactive so if you’re trying to easily hack some solution, you need to write the code, compile, make a shared library, use the library via the Ruby/Node/Python code, see if it does the thing you want, repeat.

It’s tedious. Maybe with Jank we can speed up this process?
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By Maurício Szabo, ago