[Dev-luatex] attributes
Hans Hagen
pragma at wxs.nl
Sun May 27 14:08:00 CEST 2007
Chris Rowley wrote:
> Taco wrote --
>
>
>> When replying, please edit your Subject line so it is more specific
>> Hans and I are working on a new feature we call "attributes".
>>
>
> Sounds like the idea we talked about in ... somewhere ...??
>
dunno, the name attribute is rather generic -)
> So is this an arbitrary dictionary (list of name, value pairs?
>
>
no, currently just an array of numbers attached to each node, the index
in the attribute
attr 1, value 10
attr 5, value 32
so, when attr 5 deals with color, teh value 10 can represent a specific
color; eventually this will result in a pdfliteral or special to be
inserted but that's up to the user (macro writer); such insertion can
take place for instance at shipout time by manipulating the final node
list (then typeset content)
>> An attribute is an item that becomes attached to the actual nodes
>> that are to be typeset.
>>
>
> But what is a `node to be typeset'? Or is this deliberately vague?
>
the node lists at each stage ... after boxing, before line breaking,
what enters the output routine (linebreaking done then);
> Anything in an hlist or vlist? Or only character(/glyph??) nodes?
>
anything ... glyphs, glue, penalty, whatsits, h/vlists ...
luatex only provides generic mechanisms are provided, (i.e. opens up the
engine and adds a few features that we think that should be there); one
can use attributes to implement for instance color, but the actual
implementation is up to the macro package writer (ok, i will probably
provide some generic code, but even then, the interfaces on top of that
may differ)
Hans
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