>>>>
>>>> context.blackrule{ width = number.topoints(tex.dimen["textwidth"]/2) }
>>
>> or just tex.dimen["textwidth"]/2 .. "sp"
>
> Wait, just so I understand: your solution would imply that
> tex.dimen["textwidth"] holds a number, not a dimension, right? (Because you
> simply concatenate it with a dimension unit). Which makes sense when I think
> of it because lua has no concept of dimensions, only of strings, functions,
> tables, numbers... Whereas the Wolfgang implies that the result is already in
> sp. So who's right?
both :)
tex.dimen holds a number, that is the size in points, multiplied by 65536/1pt,
so for example 3pt becomes
3pt * 65536
----------- = 3 * 65536 = 196608
1pt
This number is also known "sp". So if you store the number 3*65536 in
tex.dimen[...], you can say:
my width is \directlua{ tex.dimen[...] / 2}sp (results to "my width is
196608sp", which you can use as an argument to whatever needs a length)
or
my width is \directlua{ number_to_points(tex.dimen[...]) } where
number_to_points is something like
number_to_points = function (amount_in_sp)
in_pt = tostring(amount_in_sp / 65536)
return in_pt .. "pt"
end
which gives "3pt".
Patrick
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