Awelon Progress Report VIII

In the seven weeks since my last report, I’ve primarily focused on growing my AO dictionaries. This was my intention.

Seven weeks ago, I had 1298 words. I’m now up to 2395 words (an 85% increase), including 605 documentation words, 134 test words, and 310 Lisp-based `car/cdr/cdaddr` words (in five variations, including a functional `setcadadr!`). Many of these are undocumented intra-functional words, e.g. for the word `foo` that processes a tree I might implement multiple words of the form `tree.foo`, `leaf.foo`, and `node.foo`. The word `foo` then arranges inputs on the stack and applies the fixpoint.

In addition to the trivial Lisp-based words, development was in four main areas: streams, processes, pseudo-random number generation, and binary search trees.

I’m not entirely satisfied. I had hoped at this point to be finished finger tree sequences and maps based on self-balancing binary search trees. But I’ve only gotten so far as prototyping maps with a plain old imbalanced tree.

In addition to my primary efforts, my secondary efforts include:

  • Shift my ad-hoc document-based ‘TODO’ lists into the Github issue tracking system. (incrementally ongoing!)
  • Efficient binary representations in ABC, at least for storage and transmission. This issue kept distracting me when I was working on words for bit-stream processing.
  • Candidate algorithms for compression for ABC resources. I’m leaning towards a variation on LZSS at this point that guarantees 1:64 worst-case expansion (in addition to the 1:128 overhead for large binaries). Most of ABC should compress very well with LZSS.
  • Developed a fixpoint combinator with static transport overhead. Before, fixpoint required 2N+8 bytes to fixpoint an N-byte block. It now requires N+30 bytes and is more amenable to optimization and compression. This avoids exponential expansion for layers of recursive processes, and should result in more efficient storage and transport of ABC.
  • Attempting to more clearly express my ideas, especially why I’m developing a new bytecode to start with. I’ve expressed some of them in the code as material post, though that only hits one aspect and doesn’t really touch the importance of streamable code to my vision for Awelon project. I’ve also tried to tweak the AboutABC opening a bit.
  • Developed a model for cryptographic value sealing that is simple in both concept and implementation, and that I feel is promising enough to prototype. Progress here was triggered largely by the development of efficient binary representations sufficient for cryptographic values. Value sealing is a much more accessible model of cryptography than experienced in most conventional languages.

While I might wish for faster progress, I’m certainly feeling the difference these last couple months have made.

What’s Next?

I shall continue developing the dictionary as my primary effort. Despite my progress, I’m still a few layers of abstraction below implementation of type systems, grammars, constraint models, optimizing compilers, web services, abstract runtimes and VMs, and so on.

Eventually, around 5k-10k words, I’ll start to feel the limits of my current implementation. Every 1k words takes about 0.1s to load into memory, more if using the rather ad-hoc prototype of separate compilation.

When it becomes intolerable, or (more likely) if I feel enough progress has been achieved to develop web-apps and an ABC-to-JavaScript compiler in AO, I’ll shift my efforts towards re-implementing AO and ABC development environments as web services, with a more persistent database that can be incrementally updated, tested, etc. and never needs to be reloaded. I have many ideas for a more visual ‘live programming’ development environment that could be implemented in a browser, in addition to a wiki-like experience.

Compilation to native code, C, OpenCL, LLVM, or similar will still be an important target. Kyle Blake is developing abcc, an ABC to C compiler (at the moment), as part of a graduate project.

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