A macro which gives a random name

A macro which gives a random name

[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
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___________________________________________________________________________________

Re: A macro which gives a random name

[Wolfgang Schuster]

> 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

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___________________________________________________________________________________

Re: A macro which gives a random name

[Otared Kavian]

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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
> ___________________________________________________________________________________


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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
___________________________________________________________________________________

Re: A macro which gives a random name

[Otared Kavian]

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.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
> ___________________________________________________________________________________

___________________________________________________________________________________
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
___________________________________________________________________________________

Re: A macro which gives a random name

[Hans Hagen]

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 <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
>> ___________________________________________________________________________________
>
> ___________________________________________________________________________________
> 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
> ___________________________________________________________________________________
>


-- 

-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
     tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com
                                              | www.pragma-pod.nl
-----------------------------------------------------------------
___________________________________________________________________________________
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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archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________

Re: A macro which gives a random name

[Otared Kavian]

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 <pragma@wxs.nl> 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 <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
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>>> ___________________________________________________________________________________
>> 
>> ___________________________________________________________________________________
>> If your question is of interest to others as well, please add an entry to the Wiki!
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>> maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
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>> 
> 
> 
> -- 
> 
> -----------------------------------------------------------------
>                                          Hans Hagen | PRAGMA ADE
>              Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
>    tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com
>                                             | www.pragma-pod.nl
> -----------------------------------------------------------------
> ___________________________________________________________________________________
> 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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> archive  : http://foundry.supelec.fr/projects/contextrev/
> wiki     : http://contextgarden.net
> ___________________________________________________________________________________

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___________________________________________________________________________________

Re: A macro which gives a random name

[Hans Hagen]

On 4/19/2015 9:51 AM, Otared Kavian wrote:
> 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?

i just wanted a starting point (after all you put them in there) but you 
can start out

local ListOfNames = { "unset" }

> 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?

no, one of the context ones (see cld manual for more) ... lots of such 
helpers

> 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.

something

string.strip(io.loaddata(resolvers.findfile("foo.txt")))

or

\cldloadfile{foo.txt}


> 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 <pragma@wxs.nl> 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 <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
>>>> ___________________________________________________________________________________
>>>
>>> ___________________________________________________________________________________
>>> 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
>>> ___________________________________________________________________________________
>>>
>>
>>
>> --
>>
>> -----------------------------------------------------------------
>>                                           Hans Hagen | PRAGMA ADE
>>               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
>>     tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com
>>                                              | www.pragma-pod.nl
>> -----------------------------------------------------------------
>> ___________________________________________________________________________________
>> 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
>> ___________________________________________________________________________________
>
> ___________________________________________________________________________________
> 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
> ___________________________________________________________________________________
>


-- 

-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
     tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com
                                              | www.pragma-pod.nl
-----------------------------------------------------------------
___________________________________________________________________________________
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
___________________________________________________________________________________