Re: MetaPost with Multiple Variable Sections

Re: MetaPost with Multiple Variable Sections

[Jeong Dal]

Dear Jeroen,

If you change “pair a;” to “numeric a;” in the second MPcode, it draws a circle without error.

Best regards,

Dalyoung

> 
> \placefloatright{}{
> \startMPcode
> pair a;

numeric a;

> a := 2cm;
> draw fullcircle scaled (2*a);
> \stopMPcode}
> 
> \stoptext
> 

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Re: MetaPost with Multiple Variable Sections

[Aditya Mahajan]

On Wed, 18 Sep 2019, Jeroen wrote:

> \startMPcode
> pair a;
> a := 2cm;

You define a to be a pair and then assign it to a number. Metapost is 
telling you that you cannot do that:

>> (xpart a,ypart a)
>> 56.6929
! Equation cannot be performed (pair=numeric).
<to be read again>
;
<*> pair a; a := 2cm;
draw fullcircle scaled (2*a); ;
I'm sorry, but I don't know how to make such things equal.
(See the two expressions just above the error message.)

You can fix that by saying

numeric a;
a := 2cm;

One needs to keep in mind that all the code in multiple MPcode 
environments are run in the same scope. I occasonally use

\startMPcode
begingroup;
...
endgroup;
\stopMPcode

to avoid interference.

Aditya
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MetaPost with Multiple Variable Sections

[Jeroen]

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I have been working with MetaPost as following, which worked fine with one
startMPcode section with variables, but with 2 startMPcode Metapost
sections, it keeps telling me the numbers dont add up:


\definefloat      [floatright][figure]
\setupfloat       [floatright][default={right,none}]
\setuplayout      [backspace=20mm,width=170mm,topspace=20mm,height=250mm]

\starttext

\placefloatright{}{
\startMPcode
pair a, b;
a := (0,0);
b := (50,50);
draw a -- b;
\stopMPcode}

\placefloatright{}{
\startMPcode
pair a;
a := 2cm;
draw fullcircle scaled (2*a);
\stopMPcode}

\stoptext


I also have tried with the startbuffer combination as below, but this gave
the same error codes. Is there any other way of working with multiple
MetaPost sections with variables in a single document?


\definefloat      [floatright][figure]
\setupfloat       [floatright][default={right,none}]
\setuplayout      [backspace=20mm,width=170mm,topspace=20mm,height=250mm]

\starttext

\startbuffer
\startMPcode
pair a, b;
a := (0,0);
b := (50,50);
draw a -- b;
\stopMPcode
\stopbuffer

\floatright{}{\getbuffer}

\startbuffer
\startMPcode
pair a;
a := 2cm;
draw fullcircle scaled (2*a);
\stopMPcode
\stopbuffer

\floatright{}{\getbuffer}

\stoptext

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