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13 commits

Author SHA1 Message Date
Subramanya Sastry 8174c9dafc First attempt implementing rewriting rules on the DOM
- This is implemented as a post-processing pass.
- Might require additional checks to verify rewriteability.
- Implemented as a pair-wise tag DOM minimization strategy,
  i.e. it takes tag pairs (B, I) for ex, and attempts to
  normalize the tree just for those tag pairs.  Normalizing
  across multiple tags is implemented as pairwise rewriting
  across all pairs:  Ex:(b,i), (b,u),(i,u) for (b,i,u)
- Copied over attributes as part of rewriting, but some of the
  attributes lose their meaning on rewriting since tags are
  reordered (ex: sourcePosn, sourceTagPosn). How do we handle this?

Output examples and possible issues to fix:
   <i><b><u>biu</u></b></i><b><u>bu</u></b><u>u</u>
gets rewritten to:
   <u><b><i>biu</i>bu</b>u</u>

But, the equivalent wikitext form:
   '''''<u>biu</u>''''''''<u>bu</u>'''<u>u</u>
does not get rewritten because of parsing differences.
This wikitext gets parsed into:
   <i><b><u>biu</u>'''</b></i><u>bu<b>u</b></u>
The extra ''' token in the middle thwarts DOM rewriting.

However, a slightly different version:
   "'''''<u>biu</u>''<u>bu</u>'''<u>u</u>"
gets properly normalized to:
   <u>'''''biu''bu'''u</u>

An alternative, but fun strategy to play with is to use the following
two normalization primitives: S(wap) and M(erge).
- S rewrites T1(T2(x)) into T2(T1(x))
  (ex: <b><i>foo</i></b> ==> <i><b>foo</b></i>)
- M rewrites (T(x),T(y)) into (T(x,y)).
  (ex: <b>foo</b><b>bar</b> ==> <b>foobar</b>)

The current rewriting strategy could possibly be re-implemented as S-M
rewriting.  The problem to solve there would be to find an efficient
rewriting strategy that is guaranteed to lead to a normal form.  I may
not play with it now, but just documenting it for later (to play with
in my spare time).

This commit is just as a record of fun/experimental code where I get to
learn details of JS, wikitext, parsing, and DOM manipulation.  Next
version of this code will attempt to introduce minimal DOM restructuring
across multiple tags at once which can be more efficient.

gwicke: Removed now passing test from whitelist, and updated another whitelist
entry which is now improved.

Change-Id: Ie97bcb164eb62c34ba61aa76ba2f4c232aa713d8
2012-05-29 08:17:57 +02:00
Gabriel Wicke 8368e17d6a Biggish token transform system refactoring
* 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
2012-04-25 16:51:36 +02:00
Gabriel Wicke 001194b140 Replace console.log with console.warn in all debug statements 2012-02-14 20:56:14 +00:00
Gabriel Wicke a122e51eec Move data-* annotations into separate object on tokens, that is then
serialized into a single data-mw-rt attribute if present. Update parserTests
to ignore this attribute for comparisons with expected parser output.

A few more tweaks and notes are thrown into this commit too. 233 tests are
passing now.
2012-02-11 16:43:25 +00:00
Gabriel Wicke 7f579398c7 Use isBlockTag in DOMPostProcessor 2012-01-17 18:30:22 +00:00
Gabriel Wicke f4081bef08 First template expansion tests start working, and a bug fix in
DOMPostProcessor paragraph wrapper. 187 parser tests now passing.
2012-01-14 00:58:20 +00:00
Gabriel Wicke 6cd95fea37 Fix up constructors in EventEmitter inheritance and tweak a few more comments. 2012-01-04 12:28:41 +00:00
Gabriel Wicke 4c4a24f0a0 Hook up the DOMPostProcessor using events as well, and rename the subscription
methods to tell a story. Also document idea on how to dynamically configure
the pipeline depending on event registrations in comment.
2012-01-04 11:00:54 +00:00
Gabriel Wicke a09aa4d599 Add rough HTML DOM to WikiDom conversion. You can see serialized WikiDom of
parser tests using 'node parserTests.js --wikidom'.
2011-12-14 15:15:41 +00:00
Gabriel Wicke 1760210d13 Fixes to tables, headings and misc smaller stuff. Tracked down an issue caused
by improperly caching of production results, which interfered with the
flag-dependent inline_break production.
2011-12-04 19:23:24 +00:00
Gabriel Wicke 2bb512a4de A bit of tokenizer grammar clean-up and additional expected-html
normalization. 99 parser tests now passing.
2011-11-30 13:40:17 +00:00
Gabriel Wicke 127d8c8621 Simplify DOM paragraph wrapping postprocessor 2011-11-30 12:28:45 +00:00
Gabriel Wicke ae0b5f9af4 * Split paragraph handling between tokenizer and DOM postprocessor for better
html markup handling. 
* Remove global 'use strict' declarations from html5 parser. 
* Add trailing whitespace handling in dt

Overall, 55 parser tests are now passing.
2011-11-29 15:11:51 +00:00