Re: using variable for subscript in math+lua

[Philipp Gesang <Philipp.Gesang@alumni.uni-heidelberg.de>]

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···<date: 2012-10-25, Thursday>···<from: Jeong Dal>···

> Dear Hans, Lucas, Wolfgang, Aditya
> 
> Now, I write a matrix using \startluacode by the helps of  you.
> Also, I can do some operations in matrices which reduced my typing job.
> In this code, I have to give all the entries of a matrix as a table. It is good to use in many cases.
> 
> I have one more question. If the given array is as the following and it works well.
> 
> However, there might be a better way to do job using "for" iteration.
> I tired to use "i, j" in several ways but it doesn't work.  

Inside a string the variables are just bytes. To print to a
string you can interpolate with string.format() [1].

[1] http://www.lua.org/manual/5.1/manual.html#pdf-string.format

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\startluacode
  document = document or { } -- recommended: use namespace
  document.print_matrix = function (x, y)
    if not y then y = x end -- default to square
    context.startmatrix{left = "\\left(\\,", right = "\\,\\right)"}
    local schema = "a_{%d%d}" -- %d: prints integer part
    for i=1, x do
      for j=1, y do
        --- use the template defined above to print the
        --- row and column
        context.NC(string.format(schema, i, j))
      end
      context.NR()
    end
    context.stopmatrix()
  end
\stopluacode

\starttext
  \startformula
    \ctxlua{document.print_matrix(3)}
  \stopformula
  \startformula
    \ctxlua{document.print_matrix(9,4)}
  \stopformula
  \startformula
    \ctxlua{document.print_matrix(9)}
  \stopformula
\stoptext
\endinput
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> 
> Is there a way to do such a job using "for" iteration?
> 
> Thank you for reading.
> 
> Best regards,
> 
> Dalyoung
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___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
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