Surprised Wired is writing about this. Scientist is a great release from GH. I think the technique is powerful, but not particularly novel.

Repository: https://github.com/github/scientist

Scientist is cool. It's a little annoying that the article makes it seem like no one has thought of this before Github. But whatever, maybe more people will learn about the pattern and use it.

The other implicit conclusion that the article is making, that this will somehow make software more like a traditional engineering discipline also makes me a little uncomfortable. There still is no silver bullet. http://c2.com/cgi/wiki?NoSilverBullet

Forgive my ignorance, but how does this approach differ from traditional unit testing or end to end testing?

My point being that unit testing essentially gives you the same confidence in your refactoring efforts that Scientist proposes to offer. Tests already demand that your interface remains the same, and that old code does no harm when replacng legacy.

The name "Scientist" is about as good as "Engineer" or "Programmer." In other words, extremely confusing when used as a product name in a technical domain!

I got really excited about this thinking that it was something that worked outside of the code base as an interface proxy that could work cross-language.

What is the difference between this and writing your services to an API that runs behind something like haproxy that can be quickly configured to direct requests to whatever stack you like?

tl;dr small (and perhaps cool?) Ruby library?

Headline got me excited but then I ended up at the GitHub page.

The analogy does not seem to fit. Of course they built the new bridge before tearing down the old one. There is not really an option to divert traffic, it has to cross the bay.

The Scientist software copies the input and feeds it into two systems in parallel. There is no analogy for that in real life. There is no way to copy cars.

And I really hope they do not actually need to run load tests for bridges after they have been built.

> She envisions aging banks using it to upgrade decades-old Fortran code to Ruby or any other modern language.

I know it's just an article, but...

If anyone thinks they should replace working Fortran code that does numerical analysis with Ruby, they should be fired.

It's a shame GitHub puts effort into stuff like this as opposed to actually listening to their users (e.g. "Dear GitHub"). We can infer a shift from GitHub to alternate services soon from this, unless they change.

This is a really unfortunate choice of an example - the replacement bridge has suffered enormous cost overruns.

http://www.citylab.com/politics/2015/10/from-250-million-to-...

Nobody mentioned Erlang so far.

My biggest disappointment with "Scientist" is that it basically provides service which Erlang code has for free - hot code reloading. For decades now. Along with other cool features like great support for parallel execution, hierarchical monitoring and so on.

Article mentions some early user raves about this tool in context of "it allows me do refactoring!"

Of course it would help, but there are languages that either have all this cool stuff for decades (Erlang), or can allow you to do heavy refatoring without asking for help from "interesting" tools like this "Scientist" (Haskell).