[metapost] Question: [MPLib, MetaFun, ConTeXt, LuaTeX] metapost logging and message primitive?

[Colin Fraizer]

I have a METAPOST program that works fine with mpost, but fails when I try
to run it inline in ConTeXt. In order to debug it, I would like to see the
usual METAPOST logging and/or to use the METAPOST "message" primitive.

However, whenever I add "loggingall;" or a message statement to my ConTeXt
file, I encounter errors like this

%------
metapost        > initializing instance 'metafun' using format 'metafun'
metapost        > loading 'metafun':
D:/texlive/2012/texmf-dist/metapost/context/base/metafun.mpiv
! terminal:
%-------

What is the appropriate way to debug problems with inline METAPOST code in
ConTeXt?

My example file is:
%-------
\loggingall

\starttext
\framed{Hello world.}
This is a simple_test.

\startMPpage
loggingall;
fill fullcircle scaled 1in withcolor blue;
label.top(btex This is a test. etex, origin);
\stopMPpage

\stoptext
%-------

I am using TeXLive 2012 on Windows.

I apologize for any vagueness in this question. I'm not really sure how the
various pieces fit together.

Thanks for your help.
--Colin