Hi Wolfgang,

Thanks for your attention, but the problem with your solution is that each instance of \RandomFunctionName changes the name chosen, but I need something wihich remains the same name within a given situation (say each problem) but changes from problem to problem. 

For instance when using your solution with the source code

Give an example of a function $\RandomFunctionName : {\Bbb R} \longrightarrow {\Bbb R}$ which has a 
derivative only at the origin, and such that $\RandomFunctionName(0) = 1$.
gives:
Give an example of a function 𝐺 : R ⟶ R which has a derivative only at the origin, and such that 𝑊(0) = 1. 

while what I need is 
Give an example of a function 𝐺 : R ⟶ R which has a derivative only at the origin, and such that G(0) = 1. 

(The macro I sent earlier does this, but unfortunately it cannot use the solution you sent).
Is there a solution ?

Best regards: OK

On 18 Apr 2015, at 19:23, Wolfgang Schuster <schuster.wolfgang@gmail.com> wrote:


Am 18.04.2015 um 18:55 schrieb Otared Kavian <otared@gmail.com>:

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

___________________________________________________________________________________
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
___________________________________________________________________________________