Re: [NTG-context] A macro which gives a random name

19 Apr 2015

      Hi Hans,

Many thanks for your wonderful code… 
I modified a little bit the names you use in your code so that it may be used for other purposes as well (for instance if one wishes to select at random a certain number of exercises from different subsets among a huge a dataset of problems).
Again, for other people's possible needs, I put the modified code below (I don’t know in what category one might put your solution on the Wiki).

If I may ask three questions in order to understand better your code, I would like to know 

1) Why is it necessary to have this line (please see below)
	local ListOfNames = { "G" , "W » }
in the luacode. Is it only a sort of intitialisation?

2) You use a built-in function 
	utilities.parsers.settings_to_array(list)
is it a ConTeXt function defined somewhere in the core, or a Lua function?

3) Assuming one has a list of names in a file names (say in a comma separated format) in a file
	named my-list.tex
how is it possible to use it in \SetListOfFunctionNames? Using
	\SetListOfFunctionNames[\input named my-list.tex]
results in an error since \directlua does not accept \input.

Best regards: OK
%%%% begin choose-random-names.tex by Hans
\startluacode
   local ListOfNames = { "G" , "W" }
   local ChosenName  = ListOfNames[1]

   function document.SetListOfNames(list)
       ListOfNames = utilities.parsers.settings_to_array(list)
   end
   function document.GetChosenName(new)
       if new then
           ChosenName = ListOfNames[math.random(1,#ListOfNames)]
       end
       context(ChosenName)
   end
\stopluacode

\def\SetListOfFunctionNames[#1]{\ctxlua{document.SetListOfNames("#1")}}
\def\NewFunctionName     {\ctxlua{document.GetChosenName(true)}}
\def\FunctionName     {\ctxlua{document.GetChosenName()}}

\SetListOfFunctionNames[a,b,c,d]

\dorecurse{10}{
   Give an example of a function
       $\NewFunctionName : {\Bbb R} \longrightarrow {\Bbb R}$
   which has a derivative only at the origin, and such that
       $\FunctionName(0) = 1$.
   \par \hairline\par
}

\stoptext
%%%% end choose-random-names.tex by Hans
...
On 18 Apr 2015, at 22:36, Hans Hagen  wrote:
On 4/18/2015 10:24 PM, Otared Kavian wrote:
...
Hi again Wolfgang,
Thanks to your hint, I could solve the problem…
In case someone else would encounter a similar problem to solve, below is a macro which chooses an element from a list, it creates a control sequence (CS) containing that element and it keeps the CS until the next time the macro is invoked again to choose another element.
Thanks again and best regards: OK
%%%% begin choose-element.tex
\setuprandomize[1989] % set a seed
\starttext
% here is a list from which a name is chosen
\startluacode
  ListOfNames = {'F', 'G', 'u', 'v', 'W'}
\stopluacode
% this macro has two arguments:
% the first argument is the control sequence name attached to Chosen,
% the second argument is the name of the list from which something is chosen
\define[2]\RandomChoice{%
  \setevalue{Chosen#1}{\ctxlua{%
      local listsize = \letterhash #2 ;
      local LName = #2 ;
      tex.print(LName[math.random(1,listsize)])}}}
\dorecurse{10}{\RandomChoice{Function}{ListOfNames}%
Give an example of a function $\ChosenFunction : {\Bbb R} \longrightarrow {\Bbb R}$ which has a derivative only at the origin, and such that ${\ChosenFunction}'(0) = 1$.\par \hairline\par}
\stoptext
%%%% end choose-element.tex
\starttext
\startluacode
   local FunctionNames = { "G" , "W" }
   local FunctionName  = FunctionNames[1]
function document.SetFunctionNames(list)
       FunctionNames = utilities.parsers.settings_to_array(list)
   end
   function document.GetFunctionName(new)
       if new then
           FunctionName = FunctionNames[math.random(1,#FunctionNames)]
       end
       context(FunctionName)
   end
\stopluacode
\def\SetFunctionNames[#1]{\ctxlua{document.SetFunctionNames("#1")}}
\def\NewFunctionName     {\ctxlua{document.GetFunctionName(true)}}
\def\GetFunctionName     {\ctxlua{document.GetFunctionName()}}
\SetFunctionNames[a,b,c,d]
\dorecurse{10}{
   Give an example of a function
       $\NewFunctionName : {\Bbb R} \longrightarrow {\Bbb R}$
   which has a derivative only at the origin, and such that
       $\GetFunctionName(0) = 1$.
   \par \hairline\par
}
\stoptext
...
...
On 18 Apr 2015, at 19:23, Wolfgang Schuster  wrote:
...
Am 18.04.2015 um 18:55 schrieb Otared Kavian :
Hi everyone,
In the example below I define a macro which chooses at random a name from a list of names. But I wonder whether this can be done in a more clever way without using a numerical macro created with math.random in Lua. The shortcoming of the macro below is that before hand I must know the nomber of elements in the list of names (for instance 5 in the example below), while it may happen that I need to create as many as random names that there are elements in the list, but sometimes I don’t know what is this number.
Thanks for any insight and help.
Best regards: OK
%%%% begin random-names.tex
\setuprandomize[2015] % set a seed
\starttext
\startluacode
  Name = {'F', 'G', 'u', 'v', 'W'}
\stopluacode
\define[3]\RandomName{%
  \setevalue{Named#1}{\ctxlua{tex.print(math.random(#2,#3))}}}
\define\RandomFunctionName{\ctxlua{tex.print(Name[\NamedFunctionNumber])}}
\dorecurse{10}{\RandomName{FunctionNumber}{1}{5}%
Give an example of a function $\RandomFunctionName : {\Bbb R} \longrightarrow {\Bbb R}$ which has a derivative only at the origin, and such that $\RandomFunctionName(0) = 1$.\par \hairline\par}
\stoptext
%%%% begin random-names.tex
You can access the size of your Name table with #Name but have to replace # with \letterhash when you use it in a TeX command because # is already taken for the TeX arguments.
\starttext
\startluacode
  Name = {'F', 'G', 'u', 'v', 'W'}
\stopluacode
\define\RandomFunctionName
 {\startlua
  local listsize    = \letterhash Name ;
  local randomvalue = math.random(1,listsize) ;
  context(Name[randomvalue])
  \stoplua}
\dorecurse{10}{Give an example of a function $\RandomFunctionName : {\Bbb R} \longrightarrow {\Bbb R}$ which has a derivative only at the origin, and such that $\RandomFunctionName(0) = 1$.\par \hairline\par}
\stoptext
Wolfgang
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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
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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
___________________________________________________________________________________