[NTG-context] Reset environment between MetaPost graphics?

[Hans Hagen]

On 1/20/2022 2:59 PM, Vincent Hennebert via ntg-context wrote:
> Hi,
> 
> Say I’m writing a document containing many independent MetaPost
> figures. I don’t want to bother with enclosing each and every graphics
> in a ‘begingroup...endgroup’ with the appropriate ‘save’ statement. But
> I don’t want variables from previous graphics to leak into following
> ones either.
> 
> Like this:
> 
> % SOF
> \starttext
> 
> Text about some topic.
> 
> \startMPcode
> u=1cm;
> draw (-u, u)--origin--(u ,u);
> \stopMPcode
> 
> Now on to another topic.
> 
> \startMPcode
> u=2cm; % Triggers an error: Inconsistent equation (off by 28.34645)
> draw (-u, u)..origin..(u ,u);
> \stopMPcode
> 
> \stoptext
> % EOF
> 
> Is that achievable?
you could do

   save u; u = 1cm;

or

   u := 1cm;

or

   numeric u; u := 1cm;

or you could use a dedicated instance (normally not needed)

Hans


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