Baroquebobcat

This Sunday, I wanted to merge master into newast again. A few bugs have been fixed since then, and I wanted to have the tests for those bugs in the newast branch, since that’s the future. I’d also cleaned up some of the tooling around running commands and wanted those changes merged in. Because I’m stubborn and hard headed I tried to actually merge master into newast, but that wasn’t a great option

There were too many conflicts. Too many. And I couldn’t tell which ones were new changes and which when just things that were different. After making a couple attempts at using a merge and trying to break up the pieces one way or another, I found the answer. _git cherry-pick_ ftw. With cherry pick I could just merge the changes that had happened since the last merge–(https://github.com/mirah/mirah/compare/9a06b834…a86c3651) and not have to worry about all the other differences between the branches.

It worked pretty nicely, I cherry picked most of the changes without problems. Some of the commits that changed code that doesn’t exist any more, or has been converted to using the visitor pattern needed some modifications, but it was really straight forward.

What I didn’t merge in: bootclasspath

The –bootclasspath flag changes touched a number of things that I didn’t want to dig into this week, so I left those out. Fortunately, those changes were well factored, so I didn’t have to change much outside the commits making up that feature. I’m planning on checking that out next week. Check out this commit for more info.

In the future

Next time I work on a bug on master, I’ll try to get both newast and master fixed–if it makes sense. Doing it that way will make sure that they don’t get too out of sync.

Happy mirah hackathon day! Mirah is simply freaking awesome. @mirahlang

— Bruce Hauman (@bhauman) April 10, 2012

Last week wrapped up the Mirah Hackathon–two weeks of concentrated effort on Mirah. Check out the commits (github.com/mirah/mirah/compare/6d0821f5ba1122…f5fdb071). 46 commits! What does it all mean!?

First let me explain: in March, Ryan Brown organized the hackathon so we could put some serious work into the newast branch–which is the future of Mirah. What’s the newast branch? It is the beginnings of moving Mirah’s compiler into Mirah, starting with the Abstract Syntax Tree. I’ve done some work with it before, but over the last two weeks I saw a bit more of how it works than before.

So far I like where it’s going. The Ruby version of the compiler used methods on the AST node classes to do transformation, inference and compilation. That’s not great for encapsulation, but is pretty convenient. Newast uses a visitor pattern(http://en.wikipedia.org/wiki/Visitor_pattern), which makes it easier to modularize the compiler. It’s also easier to add new things that walk the tree.

The goals were ambitious

* Documentation: what works, what doesn’t (and should), getting started, etc
* Test writing to fill out gaps (this can kinda go along with documentation)
* Codebase cleanup (on the new newast branch…may need to wait for
Ryan to get it working well)
* Bug tracker triage (close working bugs, try to fix simple ones, file
unreported issues from mailing list)
* Get pindah (Android framework) working (if it is not) and document
how to do it.
* Get dubious (GAE framework) working (if it is not) and document how to do it.
* Port parts of Mirah’s Ruby code into Mirah (this is a goal of newast branch)

To me it seems like the hackathon ended up mostly focusing on

* Codebase cleanup (on the new newast branch…may need to wait for
Ryan to get it working well)
* Port parts of Mirah’s Ruby code into Mirah (this is a goal of newast branch)

As well as, getting some generics support in.

Before the hackathon, newast could run tests, but not that many were passing. Quite a bit of the basic functionality worked, but there was no block support and no macro support. Also, the parser was a pain to build, because it required a special branch off of master to be checked out, and the Rakefile of the parser to be modified to point at it.

After, newast is easier to build, blocks and macros work better and there’s some generics support.

Simple blocks work and simple macros work. Not all the builtins have been added yet, but the pattern for adding more is pretty straight forward.

Also, it’s become pretty easy to get the newast branch running locally. This rocks because it’ll make it that much easier for people to contribute.

Mirah on newast has some support for generics now. Mirah can now take advantage of methods and return types that are parameterized. It can’t define generics itself yet. For more information about the generic support, checkout the wiki page (mirah wiki) on it.

Overall I think the hackathon was a success and we should totally do it again.

Links

• hackathon announced on mailing list
• planning the week before
• suggested tasks
• It was even on hacker news
• Most of the discussion during the hackthon was over IRC. The logs are on donttreadonme.co.uk/mirah/