Re: Metapost example and code

[Hans Hagen <pragma@wxs.nl>]

At 12:53 PM 4/29/01 +0200, Johannes Huesing wrote:
>Hi all,
>
>I am trying to define a start-stop-environment which allows me to
>prettyprint MetaPost code and display its results. This is what I
>tried:
>
>
>%%%% code begins here %%%%
>\runMPgraphicstrue
>
>\def\PreMPExample{\startbuffer[mpe]}
>
>\def\PostMPExmaple{\stopbuffer%
>   \startMPgraphic
>     input mpe.tmp;
>   \stopMPgraphic
>   \placeMPgraphic[right]{none}
>   \expandafter\startMP
>     \input mpe.tmp
>   \stopMP
>   }    
>\starttext
>\stoptext
>
>\startMPExample
> draw
> for i=0 upto 4:
>   (50, 0) rotated (i*144) --
>  endfor
> cycle;
>\stopMPExample
>
>\stoptext
>%%%% code ends here %%%%
>
>and this is what I got:
>
>%%%% messages begin here %%%%
><mpe.tmp>
>! Undefined control sequence.

Buffers cannot be used in macros (although a workaround is to use
\definebuffer); but, why not use: 

\def\startMPExample#1\stopMPExample%
  {\startuseMPgraphic{MPExample}#1\stopuseMPgraphic
   \placefigure[right]{none}{\useMPgraphic{MPExample}}}

\startMPExample
 draw
 for i=0 upto 4:
   (50, 0) rotated (i*144) --
  endfor
 cycle;
\stopMPExample

Or simply: 

\startuseMPgraphic{MPExample}
 draw
 for i=0 upto 4:
   (50, 0) rotated (i*144) --
  endfor
 cycle;
\stopuseMPgraphic

\placefigure[right]{none}{\useMPgraphic{MPExample}}

Hans
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                                  Hans Hagen | PRAGMA ADE | pragma@wxs.nl
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