* Tokens are now immutable. The progress of transformations is tracked on
chunks instead of tokens. Tokenizer output is cached and can be directly
returned without a need for cloning. Transforms are required to clone or
newly create tokens they are modifying.
* Expansions per chunk are now shared between equivalent frames via a cache
stored on the chunk itself. Equivalence of frames is not yet ideal though,
as right now a hash tree of *unexpanded* arguments is used. This should be
switched to a hash of the fully expanded local parameters instead.
* There is now a vastly improved maybeSyncReturn wrapper for async transforms
that either forwards processing to the iterative transformTokens if the
current transform is still ongoing, or manages a recursive transformation if
needed.
* Parameters for parser functions are now wrapped in abstract Params and
ParserValue objects, which support some handy on-demand *value* expansions.
Keys are always expanded. Parser functions are converted to use these
interfaces, and now properly expand their values in the correct frame.
Making this expansion lazier is certainly possible, but would complicate
transformTokens and other token-handling machinery. Need to investigate if
it would really be worth it. Dead branch elimination is certainly a bigger
win overall.
* Complex recursive asynchronous expansions should now be closer to correct
for both the iterative (transformTokens) and recursive (maybeSyncReturn
after transformTokens has returned) code paths.
* Performance degraded slightly. There are no micro-optimizations done yet
and the shared expansion cache still has a low hit rate. The progress
tracking on chunks is not yet perfect, so there are likely a lot of unneeded
re-expansions that can be easily eliminated. There is also more debug
tracing right now. Obama currently expands in 54 seconds on my laptop.
Change-Id: I4a603f3d3c70ca657ebda9fbb8570269f943d6b6
behavior switches are converted to tokens which set parser.environment flags during the async transformation stage.
The next step would be for handlers in the sync23 stage to generate the TOC, section edit links, and so on according to these directives.
No tests written, because the switches are consumed and don't appear in rendered html. We can test the magic word layout controls individually, once they're implemented.
Another small change was to store option flags directly in the environment object, not that it makes much difference.
Change-Id: I863fbf4be1a17d2f6c31158298dd301f19ae1137
