* 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
* All parser pipelines including tokenizer and DOM stuff are now constructed
from a 'recipe' data structure in a ParserPipelineFactory.
* All sub-pipelines of these can now be cached
* Event registrations to a pipeline are directly forwarded to the last
pipeline member to save relatively expensive event forwarding.
* Some APIs for on-demand expansion / format conversion of parameters from
parser functions are added:
param.to('tokens/expanded', cb)
param.to('text/wiki', cb) (this does not work yet)
All parameters are additionally wrapped into a Param object that provides
method for positional parameter naming (.named() or conversion to a dict
(.dict()).
* The async token transform manager is now separated from a frame object, with
the frame holding arguments, an on-demand expansion method and loop checks.
* Only keys of template parameters are now expanded. Parser functions or
template arguments trigger an expansion on-demand. This (unsurprisingly)
makes a big performance difference with typical switch-heavy template
systems.
* Return values from async transforms are no longer used in favor of plain
callbacks. This saves the complication of having to maintain two code paths.
A trick in transformTokens still avoids the construction of unneeded
TokenAccumulators.
* The results of template expansions are no longer buffered.
* 301 parser tests are passing
Known issues:
* Cosmetic cleanup remains to do
* Some parser functions do not support async expansions yet, and need to be
modified.
Change-Id: I1a7690baffbe8141cadf67270904a1b2e1df879a
* Added an LRU cache (using the lru-cache node module) for tokenizer output
* Mutation of nested attributes now replaces the containers. A shallow copy of
tokens is sufficient to isolate token transformations. Need to investigate
if we can actually get away without isolation and re-transformation for most
ordinary tokens.
Change-Id: I9136b1d7a1fbcc538183a319d4ecaa290d616fdf
Explained in the README how to use npm to load the dependencies and run tests. Too bad about NODE_PATH...
Don't try to find parserTests.txt in assorted places--if it isn't present, fetch from gerrit. You can symlink from core if you're developing on both parsers, and the fetch script will not overwrite.
Use __dirname in parserTests.js to allow the script to run independent of current working directory.
Change-Id: I4c8b884e91f4fdeae385c7697aff768bdd199dd5
