Re: simplifying repeated macro calls in metafun

[Otared Kavian <otared@gmail.com>]

Hi Mikael,

Thank you so much for the explanation: I am ashamed for not having read this in the MetaPost manual.

Just to make sure whether I am beginning to understand, in your example code

> z3 = whatever[z1,z2] = z0+whatever*dir(angle(z1-z0)+90));

should the second « whatever » be 

z0 + whatever*dir(angle(z2 - z1) + 90)) ;

or am I proving that I have not yet understood this wonderful command ?

Thanks again and best regards: Otared

> On 21 Jun 2021, at 14:21, Mikael Sundqvist <mickep@gmail.com> wrote:
> 
> Hi,
> 
> As is written in the MetaPost manual: Whatever generates a new
> anonymous variable each time it is used. It is very useful in cases
> where you are not interested in the value of a variable, but want to
> use it to (let MP) calculate something. Example
> 
> you have three points z0, z1, z2 forming a triangle, and you want to
> find where the altitude from z0 is intersecting the line between z1
> and z2. You can find that intersection z3 by writing
> 
> z3 = whatever[z1,z2] = z0+whatever*dir(angle(z1-z0)+90));
> 
> The first equality says only that z3 should be on the line between z1
> and z2, the second one says that z3 should be on the line through z0,
> perpendicular to the line between z1 and z2. Since MetaPost solves
> linear equations, this defines z3, and we need not to think more about
> the actual values of the "whatevers" (note that they are not in
> general equal in this example!).
> 
> Hope it helps!
> 
> /Mikael
> 
> 
> On Mon, Jun 21, 2021 at 2:07 PM Otared Kavian <otared@gmail.com> wrote:
>> 
>> Hi Aditya,
>> 
>> Thanks for the detailed file you sent to answer Dalyoung’s question and file. And going through both files I have a question.
>> I see that both of you use a function « whatever » (but is it a function ?): what does this do and where can it be used (actually I have seen Hans using this expression, but I had always thought this is just a name…
>> 
>> Best regards: Otared
>> 
>>> On 21 Jun 2021, at 06:26, Aditya Mahajan <adityam@umich.edu> wrote:
>>> 
>>> On Mon, 21 Jun 2021, Jeong Dal wrote:
>>> 
>>>> 
>>>> Hi,
>>>> 
>>>> I defined a macro definition in metafun, and draw figures using \startbuffer[] … \stopbuffer and \processMPbuffer[].
>>>> As you see in the attached code, the same macro definition is used repeatedly by changing the numeric argument.
>>>> Is there a better way to simplify the code, for example, using \dorecurse and recurselevel?
>>> 
>>> See attached. The main idea is to store the repetitive bits in \startuseMPgraphic{...} and then reuse them using \includeMPgraphic.
>>> 
>>> Aditya<mp-test.tex>___________________________________________________________________________________
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> ___________________________________________________________________________________
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> 
> maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
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