[Dev-luatex] A design philosophy question...

David Kastrup dak at gnu.org
Tue Apr 3 14:31:29 CEST 2007


Taco Hoekwater <taco at elvenkind.com> writes:

> David Kastrup wrote:
>> Taco Hoekwater <taco at elvenkind.com> writes:
>>
>>> David Kastrup wrote:
>>>> Anyway, is something like that an area that LuaTeX would actually ever
>>>> consider touching?  
>>> Perhaps one day, but definately not soon. There are a few ways out
>>> of this, but they all require dimens to occupy more than 32 bits
>>> internally, a step not to be taken lightly.
>>
>> Not at all.  For fixing rounding of the units, the following patch
>> should do it:
>
> Yes, but not now. As Hans said, it is vital in this stage to
> compare against (pdf)tex and aleph.

I understand.

> Also, this only fixes the rounding vs. truncation, not the
> deviations created by the fact that TeX talks in base10 but
> calculates in base2.

Certainly.  But at least TeX's talk is round-trippable: the 5-digit
values output by \the will convert back to the same value on input.

This kind of quality is absent from units different from "pt" and
"sp": "1in" is perhaps the ugliest example.  While TeX only does
one-way conversions with units, I consider the difference in
implementation quality disturbing, given the author.

-- 
David Kastrup


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