Re: [NTG-context] calculating with dimension unit

22 Apr 2013

      On 4/22/2013 8:48 AM, Wolfgang Schuster wrote:
...
Am 22.04.2013 um 01:13 schrieb Jan Heinen :
...
In a book I produced with ConTeXt last year, I did a lot of calculation to be able to change the layout dynamicaly.
With the actual version of ConTeXt I can't compile the book. I have tried a lot of things today ... without success.
I hope my minimal-example helps you to understand, what I want to do - and what I am doing wrong:
\starttext
\setupexternalfigures[location={local,global,default}]
\defineexpandable\ColumnA    {30mm}
\defineexpandable\ColumnB    {40mm}
\defineexpandable\ColumnABi    {\dimexpr(\ColumnA + \ColumnB)}
\defineexpandable\ColumnABii   {\ctxlua{context(\ColumnA + \ColumnB)}}
\newdimen\ColumnABiii \ColumnABiii = \dimexpr(\ColumnA + \ColumnB)
\definemeasure[ColumnA][30mm]
\definemeasure[ColumnB][40mm]
\definemeasure[ColumnBi][\the\dimexpr(\measure{ColumnA}+\measure{ColumnB})]
FYI: \the\dimexpr... will look ahead till there's something 
nonexpandable, and contrary to what one expects

\dimexpr(...)

will not stop at the ) so, although with measures it normally goes okay, 
personally I always use \relax as terminator; the \relax will be eaten 
up so there is no interference but it guarantees to stop scanning.

(I've been wondering if we should make measured \the\dimexpr..\relax 
internally which can save dimexpr at the user end.)
...
...
A  \ColumnA% ok
B  \ColumnB% ok
% I sadly get only errors when I delete the comments:
%ColumnABi: \ColumnABi
A \measure{ColumnA}
B \measure{ColumnB}
C \measure{ColumnBi}
Wolfgang
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