Unfortunately, I introduced two regressions along the way, which will require some tweaking to get fixed. No more than a day or so of work, though.
Given that the majority of the compiler is done, I went ahead and tried self-hosting last night, just for shiggles. The results were very informative.
- Garbage collection is happening too frequently and creates ridiculous stalls when collections occur during parsing and semantic analysis.
- Disabling the garbage collector causes the parser to chew up a huge amount of memory, but it makes parsing actually fast enough to bother with on large projects (like the compiler itself).
- There are still a lot of edge cases that aren't handled by the compiler - mostly bits of syntax that are strictly legal in Epoch but haven't been totally shored up yet.
- There are also a lot of built-in functions and operators that aren't recognized by the compiler yet; this is easy to fix, though.
My biggest conclusion is that the compiler will be driving a very heavy reimagining of how memory management works in Epoch. I already knew I wanted to fix some of the annoyances with how it works, such as heap-allocating all aggregate types all the time, but this is going to take more than just refinements of the existing systems.
It also brings me to a major decision point that I have been avoiding deliberately for a long time: how to handle manual memory management strategies in a type-safe way. The fundamental difficulty is that it's currently impossible to ask the language for a chunk of memory that isn't directly bound to a type - I can't even make an array of a type and do some hacky kind of object pooling.
Fixing this will take a significant amount of design and planning, to ensure I don't wind up crippling the type system or some such.
There's also going to be a lot of optimization necessary in the compiler implementation itself, and that's going to require richer language features and standard containers and all that jazz.
So while I might actually get self-hosting done by the end of the year (which was my original goal), I've unearthed a huge backlog of new stuff to work on in 2014 :-)