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
> On 18 Apr 2015, at 19:23, Wolfgang Schuster <schuster.wolfg...@gmail.com>
> wrote:
>
>
>> Am 18.04.2015 um 18:55 schrieb Otared Kavian <ota...@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
>
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