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% language=us
\usemodule[present-boring,abbreviations-logos]
\definecolor[maincolor] [r=.4]
\definecolor[extracolor][s=.1]
\startdocument
[title={MATH},
banner={complete control},
location={context\enspace {\bf 2021}\enspace meeting}]
\starttitle[title=The benchmark]
\startitemize
\startitem
Traditional \TEX\ has set the benchmark for typesetting math.
\stopitem
\startitem
It uses three categories of fonts: alphabet, symbol, extensible.
\stopitem
\startitem
Limitations in fonts have lead to some curious handling of dimensions.
\stopitem
\startitem
The fact that there is \type {\over} makes for multipass scanning and
processing.
\stopitem
\startitem
The last family counts (when entering the second pass) so one has to use very
controlled font switching.
\stopitem
\startitem
Some features (limits, integrals, primes) rely on special macros and parsing.
\stopitem
\startitem
One can end up in tricky font switching. Also, quite some fonts are loaded in
order to set up the machinery.
\stopitem
\stopitemize
\stoptitle
\starttitle[title=Todays reality]
\startitemize
\startitem
We now use \OPENTYPE\ math fonts. In fact, in \MKIV\ we always used only one
font instance (unless we mix font families).
\stopitem
\startitem
We operate in the \UNICODE\ domain, so in the end there was no need to bump the
number of families in \LUATEX.
\stopitem
\startitem
In \CONTEXT\ we use only a few font families: regular, regular r2l, bold, bold r2l.
\stopitem
\startitem
All the tricky stuff is done with the help of \LUA. This already started very
early in the \LUATEX\ project and has not changed.
\stopitem
\startitem
But we still run into issues because the available fonts are inconsistent,
incompatible, have issues and that is unlikely to change.
\stopitem
\startitem
We have a virtual font system in place that was used during the transition (when no
fonts were available).
\stopitem
\startitem
In \CONTEXT\ there are various ways to deal with shortcomings in or extensions to fonts.
\stopitem
\startitem
At some point we need to make up our minds, accept the issues with fonts, and
just fix things runtime.
\stopitem
\stopitemize
\stoptitle
\starttitle[title=The engine]
\startitemize
\startitem
In \LUATEX\ we started with a hybrid approach but eventually ended up with
more split code paths.
\stopitem
\startitem
In \LUAMETATEX\ nearly all aspects of the engine had made configurable and are under
user control.
\stopitem
\startitem
This permits experiments where we can apply old methods onto new fonts.
\stopitem
\stopitemize
\stoptitle
\starttitle[title=The tricky things]
\startitemize
\startitem
Spacing in traditional math is a combination of widths and italic correction:
we need to add them and sometimes afterwards subtract the italic correction.
In \OPENTYPE\ math we don't lie about dimensions and apply italic correction
selectively (as we have staircase kerns).
\stopitem
\startitem
Special symbols like primes are quite inconsistent wrt dimensions and positioning
and we need to catch that. We also need robust ways to collapse them to the proper
\UNICODE\ symbol.
\stopitem
\startitem
Larger variants (these \type {\bigg} things) needs some attention too.
\stopitem
\startitem
We need to map characters onto the right shaped (alphabets) because hardly
anyone will enter the \UNICODE\ math characters directly.
\stopitem
\startitem
We might want to fix scripts, italics, kern pairs etc.
\stopitem
\stopitemize
\stoptitle
\starttitle[title=Implementation]
Among the new features (introduced over a period of time) are:
\startitemize
\startitem
All kind of inter|-|class spacing parameters (in addition to what \LUATEX\
already provides).
\stopitem
\startitem
Dozens of \OPENTYPE\ font related spacing parameters (more that traditional
\TEX).
\stopitem
\startitem
Opened up additional font (and taste) related parameters (hard coded in
traditional \TEX).
\stopitem
\startitem
Opened up style related parameters (hard coded in traditional \TEX).
\stopitem
\startitem
Control codes that make the engine follow a different (the traditional) code
path (which can come in handy when testing or writing manuals).
\stopitem
\startitem
The ability to simplify the result a bit wrt characters (the engine loves to
box a lot).
\stopitem
\startitem
Efficient font, style and parameter scaling by reusing fonts and thereby
limiting the number of instances.
\stopitem
\startitem
More options to special (constructed) symbols.
\stopitem
\startitem
Let math related nodes carry around more control properties and states.
\stopitem
\startitem
Support of local changes to math parameters.
\stopitem
\stopitemize
\stoptitle
\stopdocument
% mml
% vf chars for extensibles
% noads.handlers.showtree
% noads.handlers.unscript
% noads.handlers.unstack
% noads.handlers.variants
% noads.handlers.relocate
% noads.handlers.families
% noads.handlers.render
% noads.handlers.collapse
% noads.handlers.fixscripts
% noads.handlers.domains
% noads.handlers.autofences
% noads.handlers.resize
% noads.handlers.respace
% noads.handlers.alternates
% noads.handlers.tags
% noads.handlers.italics
% noads.handlers.kernpairs
% noads.handlers.classes
% builders.kernel.mlisttohlist
% noads.handlers.makeup
% noads.handlers.align
|
